Got the pistons loaded into the block this evening (no rings). The fit is smoother than I figured it'd be without rings keeping everything squared up. Just a good coat of teflon-based lubricant on the cylinder bores and healthy amounts of assembly lube on all the bearings.
At TDC the pistons are still visibly below the deck surface.
I did some pretty crude measuring with a caliper near the edges of the bores. Seemed to be pretty consistently reading .026"-.030" down in the bores at TDC, regardless of location or cylinder I'm measuring at. The technique wasn't particularly confidence inspiring, but it's good to see the numbers are fairly consistent. I have a nice deck bridge to check the measurements in the center of the bores, just need to bring home a nice calibrated dial indicator from work to stick in it.