When making sure that top and bottom cylinder gaskets don't block any channels in the cylinder, how do you go about trimming the gaskets ?

Do you have a bracket to mount them on the cylinder and then cut along the channels with a knife? or

Do you just hold them against the cylinder and mark the gasket with a pencil and then trim with a pair of scissors? or ?


Is it normally necessary to trim the top gasket?
_________________
Poul
"If Life Gets Boring, Risk It!"
MC21SE, KISS box
MC21SP, HRC box, racing loom