You might be able to get away with it but then you'd have to replate the inner cylinder which is costly.
But if you want to perfect this setup then that's the way to go, a good piston/rings and a replated cylinder. The standard rings have too much ring end gap which loses compression, and the lining wears off if you increase the compression which is necessary for more power. http://www.uschrome.com/chromium-on-aluminum
send them the piston/rings also so they can hone it down till the ring end gap is correct.
I wouldn't pay much, I'm a total cheap ass. I'm after the cool factor with no budget. I do have a new "cylinder" head that was machined wrong. The piston drops in the top but will not make a turtle head (tapered). Was trying to find a purpose for it greater than hold down my parts bin.
Was there any noticeable difference in performance on the 50mm piston? Did it run hotter?