I guess you misunderstood the above post(s), they fit straight onto rods without any modifications, the only thing you have you do is bore cylinder 2~3mm oversize and get a different head gasket.
That will give you around stock CR.
I skimmed head to get higher CR as motor is never going to be on the street ( although it runs fine on 93 octane gas)
I've done a couple for some members here, PM me if your interested.
I think I have one more pair of GS pistons (not sure, I'm doing 2 motors for myself, this is he 5th or 6h motor I've done as 378cc) but I know I have at least one pair of Yamaha pistons which fit (XS400, did a 487cc conversion on one)
They are not as light as the Suzuki ones,(30gm lighter than stock) only a few grams lighter than stock Honda ( 6~gm)
As a by-product, I have quite a few stock~1mm oversize CB360 pistons if anyone can find a use for them ( they don't fit CB350 as they are 16mm pin instead of 15mm pin)
I have lots of fun fitting parts from different engines into-different engines in the last 30+yrs
I've done CB550 to 591cc (Its usually called a 605 kit?? modified CB750 pistons), CB400 to 490 (modified CB500f pistons), Suzuki GS1000 pistons into CJ250 (14mm overbore) Yamaha XS650 to 800cc and 860cc,Yamaha XT350~ 422cc - that was quite challenging, loads of 'stock' aftermarket stuff ( CB600~636, XR400~440, XR250~270,etc)
PJ