For the Sands' aircraft, there does not seem to be a stated range within the plans, only a single point measurement, and that is engine specific. For the Lycoming version, also contributing to where the CG resides are things that may or may not be on other people's DR1s- starter, battery, etc. I have heard of MAC being as high as 42%, with the angle of incidence adjusted on the horizontal stabilizer accordingly. I am not saying that this is acceptable, I am just stating what others have reported to me. My own CG ranges in the 26"-27" range from 0.0" position, as indicated in the plans. My tail was definitely a little on the heavy side, but you can see on earlier pages how I placed a counterbalance above the engine- especially as I did not include things like a starter and the other bits and pieces that total over 65lbs.
I hope this helps.