So long as the handle is at least twice as thick as the tips, and tapers striaght, I've had no problem with handshock (and the last one, Red Oak Sticks, can be flet moving through the handle- but have no hand shock). Making one form the board is about as easy as can be.
Make it as tall as you are, or a little shorter (here mine was 66").
As wide as you can comfortably hold, or can get. Somewhere between 1 1/8" and 1 1/2" out to midlimb. From there it tapers to light, narrow tips for speed. The ones on Red Oak Stick 1 were about 5/16".
Leave it 3/4" thick at the handle, tpaering striaght to 3/8" thick tips. The belly and the back are flat, simply carved out (which, if you drew them out straight with a yard stick, will bring it pretty darn close to finished tiller, even if you work it down with hand tools). Round the edges, more so at the belly on the handle.
Then tiller it like normal, watching for weak/stiff spots, and you're done. After a few, you'll see what's an acceptable amount of bend in the handle, or if you need to make it bend there less for your tastes and so on.