Congrats on the marten.
Try to help out on your questions.
Bait- think they see a large chunk and get greedy. I have caught them on smaller pieces of beaver but have way more success with big chunks.
Bears. Luckily I haven't had to many problems with them but know a few guys that get hit pretty hard. I would assume location helps me out and don't think many smells deter bears.
Trap prep- I cleaned the oil off and just spray painted them all and it's kept them pretty good for several seasons. I don't wax or anything beyond the paint.
Your trigger set up sounds about like mine.
Trap anchoring- I attached a longer cable to all my traps that I can loop around the tree and attached a quick link to them.
Slots. I do about what you have for spring slots but set the trap out near the front so it doesn't hit the back of the box. That could (launch the trap back) causing not ideal catches.
Converting 110s to 120s. I went that route when I started marten trapping and have nothing but problems with some of them and it was a pain to add the springs. I am waiting for Duke to come out with his new 120 pros and replace all of mine. I have some hand problems and done dealing with the converts.

Here is a batch from a couple years back. As for put ups i have not seen a good video of it. There are some folks on here that do an amazing job. I really like putting them up and have had a buddies show me when I started.
Hopefully this helps some.

Mink glands

Some quartz points!

I'm always a proponent of buying more guns. I wouldn't look for the barrel to swap, I'd go gun shopping for a lefty 7mm-08. There are a few out there.

Looks like it was a good choice to pick the Chargers.

Sir! Much appreciated.
Big, bad, Kevin!
Bob, thank you! I’m gonna need more Sierra Mist. What’s better than that!? O
Semper Fi, sir!
The legend himself! Hello, Mr. Petty!

Haven't had a weasel show up yet, so we're making do with what we have. They only have traps on one place right now. I'm hoping that I won't be so busy with work soon, and we'll get to actually chase weasles. Fortunately, the kids are really happy to catch anything.

Them sure is some funny looking weasels

Those kids of yours are doing good.

Seems I left my 40s behind.

Anyone Live Trap Beavers in Delaware or Maryland Eastern Shore ?

One today.

That could be, I have to give that tile set in the picture a try soon

Sorry for being so late !! This is mine, bought it over 40 years ago, never had a problem from it, except me breaking the looper, the model and serial number are the side pick, if you wish a different pic of it let me know !!