Look and see if MIcroshift has an all friction option. I've never used any MIcroshift but then I"ve never used brifters and only index while I could run the SunTour Command shifters with SunTour FWs (and went bact to DT after so-so indexing with Sram FWs).
The framebuilder I've worked a lot with has set up more than a few bikes with Microshift which suggests to me it has some worth.