Hi Mike,
Welcome to the world of rc addiction. I think your choice for your first build is excellent, I would build it as a four channel and maybe relax the dihedral a bit. I hope you are able to join a club so you can get your "wings" without destroying all your hard work on the first flight.
For 300 dollars you might want to look at getting a used engine, perhaps a used radio too. Here again being a member of a club you may find some great deals from fellow club members. Beware buying a used radio though as it may need new batteries etc and may end up costing more than a decent new system. If you join a club, find out what radio the use for training.
Calvi