ive searched and done a little research but haven't exactly found the right answer. with a model 25 or cool bore 28 can you use a replacement piston that was for an iron sleeved? I have a model 25 I'm building to likely cut grass again but like always the bore is scored and plan to bore or hone to next oversize with an actual hone. what about a magnesium piston? could you bore and sleeve to 31 and make basically a big bore model 28?