If you want a Hog, then wait until you can get a Hog. I want one myself, and they are a smaller "dwarf" boa (of course there are exceptions as I've heard of some getting just as big as Colombians). For price, I just saw some Hogs for sale on KS for $150 shipped.
Ball Pythons are shy and skiddish? That's news to me. Some babies can be but my subadults/big girls (~5 lbs) are all so mellow and easy to handle and will just chill out on my lap. They are very curious as well, but snakes all have different personalities. The more you work with them the calmer they become.
I'm sure you can handle a Colombian boa (I don't like the term "red tail" for them as IMO it's not really correct: I call true BCCs "red tails"). But if you're scared of it getting larger than 7 ft then I would stick to a male, just know that some males do get as large as the girls. If you're still scared, then stick to a species that won't get so large until you're comfortable to handle it/gain more experience.
Also be prepared to have a lot of space for an adult boa, I plan on using 6 ft cages for mine.
Good luck!
PS: Look into other dwarf boas, such as CAs and Nics. Those might be a good route for you if you're set on a boa.