You have a few different factors to consider. Will your patterns require a lot of tight turns? Red Oak can be a challenge to cut with very thin blades in 1/2" thick. I'd use a Number 5 blade unless you have many tight turns, then maybe try a number 3. Red Oak may break a few blades unless you take your time. I'd maybe get a dozen of each and see which works best for you.
My girlfriend has put me to work cutting out angels from 3"x1.5x1.5" exotic woods. Purple Heart, Red Heart, Cocobolo etc. I've been using number 5 blades since the patterns do not have tight turns. I usually end up breaking a blade here and there. Probably should move up to a number 7 since she keeps bringing me such dense 1.5" thick woods to cut. I keep telling her that I can make double the number of angels in half the time using pine, at much less expense, but she is hooked on the way exotic woods look ;-)
