Forestryworks has a saw I built for him (MS-440) with a BB 440 cylinder and an OEM Stihl 064 piston. It isn't that difficult. I turned a pop-up in the piston leaving .060" over the top ring locating pin which left .110" over the top ring land. I used the stock teflon-coated aluminum base gasket (0.5mm) and ended up with .024" squish. It's a good running saw that was consistently pulling around 180-185 psi on the Lisle.
Trimming the skirts isn't a big deal. A trained monkey can do it with a file. I lightened the piston quite a bit as well.
Madsaw has a BB 372 I built for him that also has an OEM 064 piston and rings. There I did not cut a pop-up in it but rather made a 1.5mm thick base gasket which left the squish at .022". That also made a good running saw. An 038 Magnum piston also makes a decent runner in a BB 372 cylinder, albeit with some work to the piston. A Husky 380 piston can also make a decent running BB 372 but it takes a lot more work.