Is it SASS-kosher to put a trap pad on your shotgun, or curve the butt?

[Begle1]

I've been using an 1887 and would like to cut down the stock and put some sort of curve onto the end to make it easier to hold against my shoulder with just my support hand.

Would it be against the rules to either A. install a curved rubber "trap"-style recoil pad onto the buttstock, B. cut a crescent shape into the buttstock, like off a carbine or C. install a lace-on leather recoil pad that had some sort of devil ears underneath it?