Red Tail Boa For Beginners

I put some heavy stuff on the top..seems to keep my boa in

I think boas make great pets. You could always look at getting some of the other smaller locals if you're worried about them getting to large.

Central American Boas are smaller boas. Females max out around 4-5 feet.

My largest female Columbian is only 30+ pounds and around 8 foot. She's around 6 or so years old. She can be a handful some times. But I also don't handle my animals all that often.

what kind of heavy stuff

just a bin full of parts for my car...camshaft and such..not to heavy but not that light prob weighs like 15-20lbs my boa has yet to find her way out of it

There are lockable cages: show case cages, vision cages, etc..
Temps and humidity are to be watched closely. I'm sure you looked into all of that.
Boas make great display animals. In a tall cage with branches, etc they will climb and perch under a light bulb, etc.. They are docile when handled ( If you handle them often enough/once or twice a week keeps them friendly).
Just remember that they are an exotic animal that gets big, has specific housing requirements, and shouldn't be handled by small children without adult supervision.
I too, recommend a male BCI. Check into the available morphs!
Let us know what you decide.