You need to realize, with a mainline on a 2% slope you have a very small allowance for a sag before the vacuum to the rest of the system is extremely compromised. A dry line is of great assistance in that case. If 1500 taps, I'd suggest a 1.25" wet line and a 1.5" dry line, however some would use 1" wet/1.25" dry.
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.