Yep that two notch trick works wonders on the plastick slide.
The metal ones have slide cutaway to tune with plus you can two notch.
#1 #2 & #4 work the best I like #2 i can cut it to be a #4 or more if i want.
SHA's can be tuned to work wit anything, The 15/15 is the hardest to tune of the SHA's.
I like a bored out 14/12 cut to 13.8mm with a ventral ending 2mm before the tube the best.