I have kept my baby RTB in a 2 ft long, 15 inch wide 6 inch tall tub for 9 months now

And guess what? She is 100% healthy, eats every time. She is THRIVING, infact she is already well over 3 ft 4 inches (and I measured her a few meals before her last shed! so shes probably even bigger lol!) not to mention she is thick!

Last time I weighed her about a month or two ago, she came in at 475 I believe? if I weighed her now I wouldn't be suprised if shes past 550 - 600 grams

All im saying is.. boas can and will thrive in a tub until you have a good upgrade (I have a 4x2x1 PVC enclosure that she will be moved into on the 19th!!)

Hope this helps!