I could try to be funny and say, "printing on uncoated arches is an expensive mistake no matter how you do it..."
Are you attempting to create a profile for the uncoated arches by using a different, less expensive uncoated paper? Just using the inexpensive paper to create a profile to use on the arches won't work at all (nor will using an inexpensive coated paper). The way the dots spread on the uncoated surface makes the profiling process different than when using normal coated papers, and the dots spread differently on different uncoated surfaces.
You could perfect the profiling process with some other uncoated paper, and then switch to the arches when you are comfortable with the process, but like I said, you wont know if any problems with the inexpensive paper are problems with the paper or problems with the method.
If you are careful (and if you are using a mac with print tool) you can create a profile with one sheet of 11x15 paper. You can get 4 11x15 sheets from a full 22x30 sheet, so I just use one of those 11x15 sheets to profile, and one 11x15 for the test print, and still have two printable sheets for real prints.
My process goes something like this, First print the ink separation page at 100 (which fits on just over a 1/3 sheet of 11x15 -- or you could just use and ink limit of 25 for shades 2-6 and and ink limit of 75 for shade 1) then print the ink sep page again at your ink limits on the second 1/3 of that sheet to set your cross over points. Then you have the rest of the sheet for printing the 21 step targets (one or two to linearize, and then the 51 step target to make an icc profile and a bullseye gradient to check your work.
Richard Boutwell