My 2 cents-
Definitely roll on the heavy server, there is no guarantee you could get transferred off that wasteland later. You can also access more things for sale on the GTN nad groups if needed for heroics.
If you end up with Q times to log in just use the following tip. Start your log in 20 mins before you really want to play and get in line. Then do your normal pre log in things like use the restroom, get a drink and or snack etc. I have done this many times and its aok.