Yes, but go with a 20" or even a 22" wide x 4 or 5" then taper to the 8".
On my commercial made 3' wide arch it has a 33" wide base stack x 7" then it tapers in 6' length to a 12" round pipe. That gives you a draw over the entire width of the arch.
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.