Alright. 8sp it is, I guess. This is my first touring build so I wasn't quite sure on gearing yet, but I'm gathering from this thread that I should find an 11-32 cassette. Is there much difference in the quality of chains? I'm more concerned about chain/cassette longevity and shifting performance than cost, so I don't mind spending an extra $10-$20 if it's going to actually be better.

The shifters I have are lightly used Shimano "Ultegra" indexed/friction, so they should last a while.

My road and MTB are both 9sp, so the bigger jumps between gears is what has me wondering about 8sp. I guess it'll probably be a non-issue once I actually ride it. If for some reason I decide I don't like the 8sp, I could probably find a buyer on CL for a lightly used shifter, cassette, and chain package and use that money to buy some 9sp shifters.