RE: Plane choice
I wouldn't suggest a DD to get your feet wet. Last year. If it were me I'd go buy a quikee and bolt the 46 in it's nose. Last year I had a Jerry Smith Outlaw with a 36 that I thought was fast until I flew my DD this year with a Rossi 40 and it's much faster.
Besides, the Q500 has landing gear and if you like it you can always build a DD. They only take a day or two to get done depending on how quick you work and how much time you have.
I have both by the way.