Husqvarna 562 markii tear down for a base gasket delete went not so well 

You need to buy yourself a vacuum/pressure tester kit if you don’t already have one. So you fry a piston.

I wonder if you could cut the piston to a flat top and base gasket delete it.

As far as machining the cylinder it looks like the first issue would be running into the trasfer caps when cutting the base. The gasket looks pretty hefty so that might be all that needs to come out to hop it up. Gasket delete and set to proper clearances. Maybe set transfers and exhaust back to stock locations after adding compression if you like where the stock powerband is at. All just a guess, i'm only halfway to being a decent builder.

My Stihl 440 had a aluminum rubber coated gasket. It wasn't that thick tho. That gasket looks like .0060+. That's beefy

Im not good at trying to build a saw,i hope you can get some good info to help you out

Amsoil Saber 50:1 that is the cleaniest 2 stroke oil try get him and you be happy.

Crud it’s set up like the 550 mkii

I'd just motoseal it and go. But i tend to be like well let's just what happens type. So I either learn hard lessons I forget quickly. Or everything works out and confirms my f it mentality.

ALL 5 SERIES SAWS FROM HUSQVARNA ARE PROFESSIONAL SAWS. XP is just the premium series. Th3 4 series is the farmer/homeowner saws