I wound up with a set of pistons made by ITM. Never heard of them, but they were cheap, available, and came with rings which claimed to be made in Japan.
The wrist-pins all measured within .1G of each other, the rings did as well, but the pistons, well ouch. 2.6g from the heaviest to the lightest. That's about 1% of the weight of the piston and represents quite a bit of aluminum to remove on such a small piston. Still, after most of two hours now the pistons are also within .1g of each other. I'll weigh them with rings and pins to make sure I don't stack any errors on assembly.
Next up, con rods. Factory rods and STD bearings. I have to build a little fixture so I can balance the big and small ends separately.
All my aftermarket valves and guides arrived and they do check out in terms of meeting factory spec for diameter and clearance, which is more than I can say for the used factory parts I had, but even at that they are on the loose side of what the manual calls for. The guides might shrink very slightly once pressed into the head I suppose.
I also spent many hours cleaning up the block preparatory to boring, honing, and coating. Hours with a die-grinder and detail disk sander removing casting roughness and flash, rounding holes, trimming down some lumpy bits. It's a silly and time-consuming way to shave a few ounces of weight, but sometimes you just have to embrace it I guess.