Depends on the snake, some will be fine taking them off the tub floor and others will not eat unless I dangle and they strike and coil. For the most part the dangling is the way to go, I find that really shy snakes sometimes fair better with having the f/t item left in the tub with them. Its all about trial and error.
I pre-scent by placing thawed items on a spare heat mat to warm them up in the snakes area.
Exactly. I have two that will eat off the tub floor and the others wouldn't even think about it.