125 gaskets

[noobi]

i want to do a piston and ring on my bike (07 EC125) , 188 NZD, 95-100USD for the piston,ring,clip,pin i know a guy
but my gasgas dealer doesnt have the stock 0.5mm base gasket, i emailed steve at motowest and he said dont change these unless you do head measurements etc. i dont want to do this
could i just run the 0.3 mm and the 0.15 mm base gaskets to get as close to 0.5mm as possible or is this dumb?

also the piston that i can get is the wiseco GP piston for nikasil bores, steve at motowest said that the plating is nikasil but i looked in the exhauset port and there looks like theres a brown mark on the inlet side of the cylinder, dad says that nikasil wouldnt have that? hes a tool maker, and been into serious aero modeling and car tuning for a long time, is dad right in saying this?

also the gasgas GP piston for an 07 ec125 is the same as a cr125 gp piston