Several guys told me about those Yosh pins, but I think they are unobtanium. I looked a long time for lightweight tapered pins and couldn't find any the length I needed.
I don't have a CB450/500 piston but try to find the length of that one. The CB350 twin piston is 64mm, but the pin is 56mm, CB750 is 53, CBX1000 is 51mm.
Maybe you'll need to taper some new Wiseco pins. I used the 3mm walled CBX1000 pins and shaved them from 44.4gm's down to 38.2.
You might also check CP Pistons, they had several options for pins.
Good Luck.