Groo here
I have an Sp101 with 4 ports,2 FA83 454's [4 3/4 and 7 1/2 in]
A trailboss 3in 44mag, and some TC contenders [ one a 45-70]
In all cases the porting does not change the recoil of the gun.
It DOES change the ROTATION of the gun, the barrel does not come
up as fast or far.
As to "Flash " given the amount that comes out of the BC gap
any out the ports is of little import.