A bit of a thread necro here, apologies...
I've used an Avery swivel set for probably 1,000 or so rivets, and while it sets rivets well, with no skin marring, it did take some practice learning to control it's tendency to "walk" while using it as a solo builder.
I had an issue setting a rivet in a corner (aileron underside up near the brackets) using the swivel head. Perhaps it's my technique, but trying to get pressure over the rivet would cause the gun to want to skitter off the rivet. I imagine if I had had another hand to hold the set in place, this would be a non issue.
I borrowed a friends straight flush rivet set similar to the Boeing anti-slip discussed here, hoping it could get into that corner area better. Wow, have I been missing out. Perhaps since I've learned riveting using the "rank bull" swivel set, using this set was, dare I say, "Easy Button" mode. No slipping, no tendency to walk.
I'm keeping both - a future helper may find the swivel set easier to use with both hands, but for solo building, I think I'm gonna have to switch to one of these.
Next question is size to order ...