I've got dubias, LOVE them. If you're nervous around them, get dubias; they don't make noise, don't climb, don't jump, don't fly, don't die. :P Hissing roaches get much larger than dubias, and they can climb REALLY well, it's difficult to keep them contained.
Start out with 200 or so adult dubia (more if you're getting nymphs), get the temps of the tub up to around 85-90*, feed them, give them fresh fruits for water, and in two months you'll have a stable colony.
(Don't feed any off until the two months are over.)