I would suggest that if it's at all possible (keeping it a surprise), to have the enclosure setup and working right before getting the BP. That way you can work out the kinks getting the humidity, ambients, and hotspot temps right. Then all you do is put the BP in and it should be good to go.
I just read that in one of the threads you guys sent me to. that shouldn't be a problem.
I was a little concerned about attaching an electric heat pad to a plastic tub but apparently that's not an issue as long as it has a thermostat.