Well...I certainly feel a lot more confident that the rebuild is heading in the right direction with regards to these pistons.
Thanks for all the help.

Now 2 other concerns come to mind.
1. Intake manifold fit
I'll need to mock this up once I get the heads back to verify bolt/port alignment & valley pan seal.
2. Pushrod length
Having non-adjustable 6-pack rockers, I'll need to verify preload is still within spec. Suspecting .030 was already taken off the heads, now I'm taking .010 more, and keeping within .020-.040 preload, I'm hoping the 3/8 x 9.310 rods I currently have will fall within this preload target.