First of all, I'd like to say hello, since I'm brand new to the forum

I know there are a lot of threads about buying binders, but I haven't been able to find one that relates to my current situation:
I'm not self supported and I've wanted to buy a binder for months now, but my parents don't really seem to care, even though they have accepted the fact that I'm transgender. Feeling desperate, I turned to my grandmother for help, and she agreed that she would order me a binder, as long as it isn't too expensive, because she is very tight on money.
So, that being said, I've looked at both Love Boat and Underworks, but seeing as my measurements are at about a D-cup, I'm not sure about ordering from Love Boat anymore, and from what I've read, T-Kingdom is out of the question for the same reason. Ordering from the U.S. at Underworks seems like a cost-efficient choice, given their reputation as the best for returning/exchanging products.
At this point, I've chosen my site to order from, but now, which one do I pick?!?!
To get this out of the way: I measure 46 1/2 inches around the bust, and 42 inches under, averaging at 44.25 inches. I've looked at and read reviews of the 997, 998, 988, and the tri-top (not sure what number that one is, let's just call it the tri-top). As reluctant as I am to post this on a public forum, I'm pretty overweight, (42/28 pants size), and although getting a long binder may compress my big belly some, I doubt it will help much, so I choose breathing over looking slightly less fat.
Looking at the 988 and tri-top, I'm afraid that if I order this, it will cut my stomach in half, seeing as I'm only 5'4.
Looking at the 997 and 998, I'm not really sure what the difference is.. But I'm thinking that if I get one of these, I could fold it over my chest, for double compression in the chest area, and no stomach compression, but I'm not really sure how that would work out, it could be
tootight. I rule comfort over flatness, because I don't have high hopes for complete flatness with my size, I plan on using some loose clothes/layers to hide what reduced chest I still have after the binder.. I'm hoping for atleast a reduction to a B-cup.
So I have questions:
1. What is the difference between the 997 and 998?
2. Are there any suggestions or tips you've got for someone of my type of build?
3. When I order a binder from Underworks, should I consider myself 44 or 45 inches? (In some, the 44 falls into a large instead of XL)
4. What are your experiences with Underworks and their models I have mentioned above?
Sorry for the long post and lots of questions, but I really want to make a careful decision, so that I don't get disappointed when a binder finally arrives. Hoping some of the more experienced bros could help me out, please and thank you

-Adam