Consider 2" PVC in 20' lengths, bell end. It would take a few more feet because you would want a expansion/contraction design every 250' or so. This is done by using an elbow, then a length of pipe, then another elbow then either continue on or side step again to original path. This allows for expansion/contraction. You could buy 2" PVC for a little less than $1800 and get good vacuum transfer. It's no good to have a big pump and then choke it on pipe size. Get a copy of Steve Childs maple Tubing Notebook, it will give you a whole new perspective on vacuum performance. A great resource.
Even though you get the same cross sectional area in 4 pipes @ 1", you get way less air flow thru 4 @ 1" than 1 @ 2", it's a matter of line friction.
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.