Doug,
I've have only done one HWH wrap so I'm no expert, but the main thing I tried to do was cut access "doors" to all of the important parts like the access panels to set the temp and replace the heating elements. I just cut a flap and then taped it back down. That way I wouldn't have to tear the wrap off to take care of any of that later on. Our last two HWHs have been gas, and very well insulated to begin with, so I haven't bothered with a wrap. The top of the unit gets a little warm but the sides stay cold even though there are gallons of piping hot water inside and our current one sits for hours without running if no one is using hot water. I decided the money and time was better spent insulating the pipe because that was where we were losing the most heat.