terrier,
I like two traps at these types of mounds, I'm a gopher rookie but use the gophinator as well. My feeling is, if I hit a recently moving litter, I may have
others coming in on their heels so just one will take one, but not 2 and 3 behind that one.
I suppose it is like many forms of trapping, when I first started I put a trap everywhere when after coyote or fox, after learning more and getting some intel from the likes of Ron Leggett I settled in to finding quality locations and setting smart.
Now of course, we are talking about a much smaller home range in the p. gopher, but I think I'm learning the same lesson, I started by blasting the place
with a grid, now I put 2 max per set of holes and move 20-30 feet to the next set. Many of my clients have just a couple, but I've got a few with 2+ acres and they can have 12-14 depending on the season and recent litter dispersal.
Love p. gopher work, don't do enough of it - like a small trapline!

Good luck!
Justin
P.S. One way to eat up 2 traps in the same tunnel area is to do the 2 way set, and I prefer that to setting one trap per exit or push out hole if that makes sense. A two way can catch two, and can get the gopher coming from either direction. A little more digging but I have some nice soil!