Passed All 6 in about 4 months. Thank you, Amber Book

I ended up taking 1 test a week for 6 weeks.  This gave me ample time to recover & mentally prepare for each successive test with a cram session each weekend and not let work interfere with the testing by taking them on Mondays.  Each weekend was basically practice tests + AB flash cards.  Outside of AHPP for PcM, PjM, CE, I didn't really use a lot of external resources.

I used the 8-week Amber Book program + an extra 2 weeks for the Michael Hanahan lectures.  I do have 9 years of commercial experience across all phases of design and construction which was helpful.  The challenge, for me, was staying focused and looking at the big picture.  There is an overwhelming amount of content and resources.  I just needed a path to follow.  Amberbook was that path.  All in all, this was about 4 months of effort once I sat down and focused.

Do treat it as one or two exams.

Michael Hanahan lectures (with powerpoint slides):
https://perkinscoie.com/professionals/michael-j-hanahan

Other resources I found helpful:
https://evolve4dllc.gumroad.com/l/PcM-PjM-CE?layout=profile
https://evolve4dllc.gumroad.com/l/PPD-PA?layout=profile
https://arevisuallearning.gumroad.com/l/DnOkN?layout=profile

Specifications (mostly division 00 and 01):
https://www.abc.org/Membership/MasterFormat-CSI-Codes-NAICS-Codes/CSI-Codes

Test Strategy:

1. no breaks
2. go through the entire thing once, flag all of the funny questions and ones you don't know. Always at least answer to the best of your ability the first time.  If you run out of time, you don't want any incomplete questions, because a guess could be correct.  If i wasn't confident, I flagged it.  See #6-7 below.
3. Try not to spend too much time on any given question.  Sounds obvious.  I got tilted on a single question on PjM for nearly half an hour.  It actually affected the rest of the test, even though I passed.  I was frustrated.  I spent 60 minutes remaining + 30 minutes in the question just hating everything.  This is not a place you want to be.  You need to keep a high degree of mental clarity and don't let minutiae distract you.  See #5 below.  What would have been a great 90 minutes to review was less than 60 without feeling great.  I didn't feel like I was able to cycle and review as well as I could have.
4. I flagged all of the hot spot questions so the second time around I would make sure I clicked in the right spot.  Same for some of the click and drag questions.  This might sound silly, but the first thing I learned from the practice exams is "read the question".  This is especially important for hot spot questions where you are instructed to click in a specific location.  It's an easy thing to miss if you are not paying attention.  I corrected myself multiple times with a second look to make sure I followed the instructions.  Where every question counts, don't miss something as easy as "not clicking in the right place" despite knowing the correct response.
5. Ideally you get through each exam with about 60-90 minutes left to review flagged questions.  More is better.
6. The goal was to have less than 20% of the exam with flagged questions by the end of it.  If I had a high degree of confidence in that I got 90% of the unflagged questions right and maybe 50% of the flagged questions right, I would pass.  Even with 0% flagged correct (assuming 20% of the test) and 90% of the rest correct, that would be a 72%.
7. Spend the remaining time cycling through the flagged questions and unflag as you feel confident about an answer.  I would end the first pass with around 25-33% of the test flagged.  PDD was like 40% and I wasn't feeling good about myself with the 90 minutes I had left.  Some of them were funny questions that I wanted to look at again, some of them were hotspots to make sure I clicked in the right spot, and others were ones I just guessed at and hopefully other questions and content would provide insight that could help answer the question.  I might see the same question 5 times and never unflag it.  It was part of my 20% pool that I could write off.
8. It's easy to second guess yourself and change correct answers to an incorrect answer.  That is why I minimized going over everything that I did not flag.  I essentially treat the flagged questions as being written off, but I spend all of my remaining time to answer them to the best of my ability because that only helps me and doesn't hurt me.

Easiest / favorite tests: PA-PPD (plays to my strengths, and I feel AB does the best in this content area)
Challenging tests: PcM, PjM (reading comprehension is as much a part of the test as the content)
Least Favorite: PDD (too much "architecture trivia")

core themes to take with you:
PcM, PjM, CE: Risk Management, Project Delivery pros & cons.  Understanding process.  Chain of command.  B101/A201/G-series.  Read / Watch the Michael Hanahan lectures.  Print copies of those contracts out and write on them while you listen to the lectures.  Diagrams and excerpts out of AHPP are valuable.  Out of all the practice tests, these were the most relevant and valuable.  As stated above -- reading comprehension is a significant part of these tests.  The practice tests really, really help you out with that if you dedicate the time to do so.
PA-PPD-PDD: Specifications, understanding how to read CDs, zoning concepts, high level acoustic, lighting, HVAC concepts, designing with climate & sun, as much IBC chapters 3/5/7/10 as you can, and a general understanding of clear floor areas from ANSI A117.1 + ramps.  I never felt like I had to memorize much for this exam, but a few things related to fire ratings and ADA were helpful (and experience kinda cements this information).  PDD has so much random stuff that it's hard to really study for, I felt.  But if you know at least 60-70% of the content, you might be able to work your way through the other 30-40%.

Seismic is a decent chunk of PPD and PDD.  Don't neglect it.  There are some fundamentals that you can understand that will help you out, despite the seemingly random questions that are asked.  I honestly only used the AB flash cards + general experience because wind loads and design is similar to seismic.