Some people believe that the snakes do associate the tank as a feeding place but i personally do not believe that. I have been feeding my snake in the tank and i have never been bitten by them. they also know my hand is not food. I think the snakes only associate feeding time when they get the smell of a rat...but anyways! If you were to feed in a different container. yes wait till you see the rat past the snakes throat and then yes you just put your snake back into the tank once he is done eating and leave him alone for the remaining days.
No it is not a big deal to change the feeding day. JUST a little hint. do not panic if the snake does not eat on that day. just take it slow and try next Thursday.