I am not sure that I actually isolated my lean problem before I fixed it. I first thought that I might have had a vacuum line come off but after checking them, they were either new or had tight connections. I did hear a ticking noise coming from the pump area, so after going thru my notes and seeing what the A/F outcome was after changing my drivers-secondary jet (farthest jet from the fuel pump) from 74,76,78,80, then 82 with no change, and after all of the weird lean issues during my previous drive, I took a stab at replacing the fuel pump.

""I discovered that some instances of my lean miss (AFR>17) are when pressing a little on the throttle. Vaccum is dropping to the 12-10" range""
- Main jet sure sounds correct to me too. You are currently using a 7.5pv, what about using a higher rated unit? Your mains might just be starting which means your pv might help being higher once the mains are full on.

""a WOT from 60MPH started with AFR in the 12's but then I watched as it dropped into the 11's then into the high 10's!"
- The first dip into the 12's sounds good. What about the rear jetting? Could it be too rich? If you go up on the primary jetting, this issue will get even richer. What about a 4-6 jet drop on the secondary side? The HSAB swap would be a quicker test though.

Note: I just make a 4 jet swap on the passenger secondary side and a 2 jet swap on the drivers secondary side and it netted me 12.0 to 13.0 on the passenger side and a 12.4 to 13.0 on the drivers side for reference. One full point with four jet sizes and about half of that with 2 jet sizes.