I just took the safety off (careful not to lose the little spring loaded steel ball for the detent).
Disassembled enough to get the striker out.
Took out the issue stroke screw.
Slotted the back end with a Dremel cut-off wheel.
Put the now slotted screw back in (slot to the rear).
Mad a skinny screwdriver to fit through the threaded hole that holds the safety on.
Did all my tuning with the safety off the rifle.
Once I got where I wanted to be, put the safety back on.
Liked the rifles so much, did it twice (.22/.177):