People don't shoot the going away target past the opposite house, because it is against the rules. As for station 8, the closest that the target gets to the station is 6 yards, so even a 2 yard long gun puts the muzzle 4 yards away. However, since a target is lost once it passes the stake, nobody tries to shoot them at the stake, with most shots being in the 5-10 yard range. We used to walk up closer to the house on station 8, and I had no issues breaking the target from 5 yards forward , using 32" barrels, with Muller extended stainless chokes that add another 1-1/2" or so to the barrels. By 10 yards forward, I was no longer consistently breaking the targets.
In the field , I don't find the 29" barrels on my 16 gauge SxS to be an issue, and that is the gun I use for shooting birds during our NAVHDA tests, where shooting can sometimes be very close when a bird flushes at me, instead of away from me.