If trying to split the purchases into 2 years, either look for a used 2x4 pan or a used 2x4 evaporator. People selling a 2x4 evaporator are very unlikely to be willing to split it up, but dealers who took them in trade would be more willing to split it. A new pan will set you back farther than an entire used 2x4 in most cases.
Check the classifieds on this site often, also check craig's list. If a pan is soldered, test for lead in the solder (test kits available at most hardware stores). Also check dealers like Bascom and any others you can find.
Then customize the block arch and buy or make a proper arch for the 2021 season.
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.