More pan tension can help, I agree. Im running about 4 pounds on that particular trap. The downside of more tension is that I sometimes have to get 5 or 10lb beavers. I have run as much as 8lbs pan tension, but video confirms that that too will cause misses because the beaver just does not fire the trap. And so it is a balancing act, and I have found that about 3.5 to 4 pounds is the best trade off.
Part of that equation is that big beaver has an 8” long foot pad and with a 7.5 inch trap, it can and will occasionally have both or one side of that pad over a lever or a jaw. That is the main disadvantage of footholds targeting back feet - there will be occasional misses and toe holds. But that is offset by the huge and beautiful advantage that a beaver simply can not avoid a well concealed blind set foothold. One can absolutely take a toenail one night, then the next night take another toenail from the same beaver in a different location, and then the third night catch that beaver in yet another location because they have absolutely no defense against a well concealed blind set foothold. When all else fails, the beaver buck stops with blind footholds. And before someone goes there, I can not set for front foot because non targets are baaaad juju in my high visibility nuisance work, and a trap set deep for a back foot almost completely eliminates non targets.
At Trapset - I never even thought about current! This creek did have some current. But right now it is a stagnant 20 acre impoundment where there should be a hay field. It will be a creek and hay field again very soon - I gave the farmer and county surveyor my word on that…..