There is no doubt Pathera will have some teething problems with all new valve and barrel systems but to have the power to shoot 40 grain .22 slugs current Crown won't be up to the task.
My slug Crown has all factory parts, I did upgrade to the brass piston from FX and FX power slug kit. The power slug kit has heavier hammer but not heavier springs, heavier hammer AND spring might just break or at least shorten the live of the valve pin.
For slug only I would get as fast of twist rate as possible because I want to shoot heaviest slugs possible. BUT I don't know if 1:14 TR is available as an option yet. Interestingly even the 700mm .22 Panthera only has the 1:16 TR which is another reason I'll be shooting the 35 grain instead of the 38 grain slugs for now.
Impact and Maverick by design has MUCH more power with MUCH bigger plenum even if the valve are the same. However I'm pushing my Crown to shoot .22 35 grain NSA slugs at 52 FPE which is NOT low power by any means, don't know too many guns that can do that with a small plenum and 600mm barrel.