A few observations on using these traps.
I have now caught 68 civets this year and I have tried setting them a number of different ways. I am now pretty confident the best way to set them is upside down. As you know I use a box and set the trap near the front of the trap. Bait in the back that I have a spike through to hold it in place. I set trap normal right side up and through a hole I have drilled in the front floor of the box I wire the leading edge of the trap tight to the floor. Now just turn the box over. Make sure the safety catch is out of the way. I also bend the end of the spring that sticks up down to give the opening a more open appearance.
The mechanics of why upside down is best.
The striking bar travels in an arc and with the civets head up it is apt to strike the civet in the nose. Any strike ahead of its ears results in the jaw pushing the civet out of the trap. This can also result in a foot catch.
Upside down the civets head is in a position closer to the what one thinks of as the bottom of the trap and the arc is longest at this point so the civet will be struck farther back. Also it can't push the civet out of the trap from that angle. If the civet has it's foot inside the trap you will catch near the shoulders which is good.
A neck catch is still common with the trap set upside down and I am still working on the best method for a run pole set as I think a neck caught civet will self dispatch better if it were to fall off a run pole.