I had a half pint for my first year making syrup. I bought it used. While the warming pan was not perfect, and it did drip a portion of the condensed steam back into the syrup pan, it did help pre-heat and thus improved the boil rate. That being said, the best I ever got out of it was between 6-7 gph. To get that I had to split the wood to under wrist size, have it fully dried and add fuel every 5 minutes. I also had to add to the warming pan every 30 minutes rather than waiting until it got low. That helped keep the temperature higher. I also ran the pan between 3/4" and max 1" deep, deeper and the evaporation rate suffered significantly.
Dave Klish, I recently ordered a 2x6 wood fired evaporator from A&A Sheet Metal which I will be converting to oil fired
Now have solar, 2x6 finish pan, 5 bank 7x7 filter press, large water jacketed bottler, and tankless water heater.
Recently bought another Gingerich RO, this one was a 125, but a second membrane was added thus is a 250, like I had.
After running a 2x3, a 2x6, 3x8 tapping from 79 taps up to 1320 all woodfired, now I'm going to a 2x6 oil fired and a 200-425 taps.