I've never understood the logic of leaving the trap unset for rats "to get used to".
Either a bucket trap or a snap trap kills them the first time they use it. What's to "get used to"? Seems they either eat the bait for five nights (unset), then eat the bait on the 6th night (set), and are eliminated. Or they eat the bait on day one of a set trap and get eliminated. Or they are wary and never eat the bait. Leaving it set seems way more effective/efficient. Why feed them for 5 days?
I think it's one of those things that sounds good on the surface, so people don't think it through any further. But when I think it through, I just don't see the point.
I agree on attaching the trap to a board, I do that with mouse traps to, on a long furring strip. It just makes it easier to set them in place, and retrieve them from an out of the way area against the wall.
-ERD50