Go boa. They are mellow, get larger enough to be impressive but not huge to require 2 people to move. Boas get on average 4-8' depending on locality, sex, and feeding. Another good choice would be a super dwarf retic but you would want a pure locality like Kalatoa. They get about 6' or so. Now if you get a morph with sd blood, its kind of a guessing game to size as to how much the mainland blood influences it but I would be prepared for 10'+. As for burm, you could get a dwarf burm which will be about 6' too but they on Lacey Act so they cant be transported across state lines.

Bottomline is if you go for a SD retic, make sure you know the parents size, how many generations of SD it is and what % SD it is or if its a pure locality.