Here are a few considerations:
If one hole is good, two are better - the double dirt hole set.
Of course with any hole set, you need to know/guess which direction the animals will be coming from: right, left, or straight on.
The trap bed doesn't need to be bigger than the outside of the trap. I always dig a deep, deep bowl under the trap, inside the jaw diameter: either to put the trap chain in if anchoring under the trap, and/or to allow water to collect and drain from under the trap or giving dirt falling under the pan a place to go without interfering its' movement.
What's the best way for the trap to be in the bed?
Like I had it or like side ways.
Single dirt hole - axis of the hinges points to the hole
Double dirt hole - axis of the hinges should bisect the angle between the holes
to reduce the chance of the foot being thrown out of the trap or a toe catch.
Underalls or polyfil under the trap pan,.or trap cover (wax paper, coffee filter, screen) whichever works for you. I prefer a commercial, waxed hamburger patty paper as a trap cover. When using waxed paper, crumple the paper up and straighten it out again to minimize noise when being stepped on by the animal.
Bed trap solid, outside of the jaws, on the ledge created when digging the bowel under the trap. Pack dirt against the outside of the jaws (use a hammer if need be). Use a couple of drywall screws under the jaws if need be to eliminate rocking on an uneven trap bed. In winter, use some form of antifreeze.
Lightly cover the trap with dirt or duff, sifting from up high (same with snow, even higher). Smooth the dirt if needed with a small broom. Remove any pebbles and clods of dirt from on top of the trap that might interfer with the closing of the jaws. For bobcats, an exposed pan is an attractant that works.
Place minimal guiding along the jaw sides of the trap, funneling the foot to the trap and the hole.
The distance to the hole/s from the trap will depend on what angle the dirt holes are dug in relative to the horizon of the ground. The more perpendicular the hole is vs. the shallower the angle (forcing the animal to crouch down to see into the hole). Watch a dog for how they approach differently angled holes. Dig holes deep and use a plug to obscure the bait or lure in the hole.
Want to see how your trap placement is preseason, punch your dirt hole/s and pace a small cylinder of PVC pipe about the size of your trap in loose dirt where you figure you would place the trap. Lure your holes and look to see if animals stepped within the ring. Adjust the ring location as the animals show you. It also indicates whether you're on location and if the lure is working for you.
When finishing the set, spray a mist of water across the the top of the set to blend everything together as the water evaporates and the set dries..
Place a natural backing across the back of the set to discourage animals coming in from the wrong side of your sets to investigate.
