HI Billy,
Since you just sent in your registration we probably have some time before the airworthiness inspection. No need to rush :-) Since the first flight experience is fresh on my mind I have too many opinions to try and cram them into a single post. So, I'll throw out a few at a time and give the more experienced pilots a chance to correct, concur, or comment. Let's just start with where you are right now. We'll see how this goes.
1) If you can find an highly experienced/current test pilot pilot to perform the first flight, by all means, that's the way to go. Keep looking. The only disadvantage to this is that after that first flight *you* still have to perform your first flight. It does relieve some of the pressure though.
2) Taxi Tests: Do a lot of it. Not high speed tests but up to maybe 30 MPH. That will get you used to the direct tail wheel steering. It will also give you a chance to memorize the site picture for landing. Keep at it until your hand moves naturally between flaps, brakes, and throttle. Maybe you will even be able to see the airspeed indicator come alive. That would be comforting. If the locals give you a hard time about it give them the opportunity to perform the first flight. That'll shut'em up.
3) I wouldn't consider performing the first flight of a tailwheel Sonex without being tailwheel current.
That's a start :-)
Edit: Here is a link to a presentation by Joe Norris on the first flight of a home built: https://www.eaa.org/videos/105192196001. I didn't find it until after my first flight. It had a couple of suggestions I should have known about.Wes