Happy to have you here on the forum!!! We hope you enjoy your stay with us
Yes, this is the right place for this; any question on care is considered "husbandry".
Question 1) If I'm not mistaken, those are the dimensions for a 20 gallon, right?? I think that is acceptable for space requirements; a lot of BP racks have smaller footprints for each tub, so you should be fine...
Question 2) No; 1 adult mouse a week will not be sufficient for an adult BP. Usually you will want to feed 10-15% of their body weight; a female at full breeding weight (1500+grams) will need more mice than one a week. This leads to
Question 3) Rats aren't "better" than mice, but one medium rat will cost the same as a jumbo mouse, but will weigh more. Thus, one medium rat a week will feed an adult BP, and will cost about the same as 1 mouse a week.
Hope that helps some....