First, weldome to the forum Aaron. Glad to have you with us.
Your paint combination should work fine. Tamiya acrylic is great paint and should give you a good finish to work with. Once it is complete and has cured for a couple of days, I'd recommend a good coat of gloss finish. There are a lot of posts here about gloss finishes, but since most (but not all!) of the gloss coats are laquers you need to be certain that your acrylic paint has completely cured before using them or they can dissolve the acrylic.
An alternative is an acrylic gloss coat. Future floor polish works well, but I usually wind up with a pebbly finish instead of a high gloss finish. Since most of what I build has a flat or "Semi-Gloss" finish that works OK for me. From posts I've read here the way to fix that is to keep spraying thin coats of Future and let them dry. After 5 or 6 coats the pebbling will go away.
I think Poly Scale makes some acrylic gloss coat as well. Testors, I believe, is laquer. There are some guys here far more familiar with them than I am who will chime in and get you pointed in the right direction.
Regardless of what you use, paint a piece of scrap sheet stryrene the same as your model and play with that until you get the finish that you want. It's a lot safer to work out problems on a piece of scrap than a finished model.