Ken, my system is similar to yours except I use a gallon zip lock to hold the rats and I use one whole side of my sink to hold the hot water. I use a weight to keep the bag submerged, and I refill the sink a couple of times. Total thawing time is usually about one hour. After they are thawed I hit them with the hair dryer to give them some some heat and get the rat smell molocules zipping around. The usual end result is BP's trying to stare a hole thru their tubs trying to figure out where the rat smell is coming from. By the time I open the tub to drop the rat in, the only real trick is getting the tongs out of the way fast enough.