Is there room for the trigger to lift and fire? Picture looks like it is tight to the lid.

Those are nice looking boxes that you built. Well thought out with the fitment of multiple trap sizes and bait retention.

Not to redirect your thread, but I have an aversion to driving nails or screws into live trees. Reason being is the amount of sap that they will weep is crazy, and I go out of my way to keep pitch off of my fur at the sets.
Something to consider, drill two sets of four holes through the bottom of your boxes to wire them to the tree or pole. This also allows them to swivel a bit when bears smack them around during the off season.

Yeah it pretty much wedges in there, I bend the edges so it gives it a little bit of spring pushing against the box. I cut a hole in the middle to so I can put my finger inside and pull it out.

Hey viking, I know the picture doesn’t show it that good but there is room for the trigger to engage. I push the trap in til there’s a bit of room on one side and I’ll bend the springs up towards the trigger so the bottom jaws are touching but the top still has a gap.

Weekend update:

Still rough country out there so it's pretty slow travelling. I got some more sets out and picked up some more fur. Didn't seem like there was a whole lot of action with the warmer temps this week. I'm expecting more volume this week with the lows dipping into the negatives. I've been using a lure with a strong lingering sweet smell which seems to be doing a good job so far. I'd alternate using the sweet and then a skunky lures when I first set and found the sweet was doing better. My brother and Junie gave me company this trip and it was a good day out in the country.

An update on the experiment:
The boxes are still undefeated against the poles 3-0. The poles were nice and dry with no snow this time. There are 3 more sets that I added to the experiment. I think it's just a matter of time that we'll see out hanging off a pole. But so far the boxes are on a hot streak.

Nice marten

That is a pretty neat design you got for your boxes!

good eyes Viking
Field modifications; a little run with the chainsaw tip cuts a grove so that the dog can rise to overcome this problem