I use the stuff from Nashbar--much cheaper than Brooks and looks nice. It's sort of light brown when it arrives, but a small amount of proofide darkens it to where it matches a Brooks saddle pretty well. I usually ride with gloves, and I avoid the rain if I can. That said, I have been caught out a few times and I have not noticed any issues with the leather once it dries.
This is Nashbar's leather tape in brown, with light proofide:
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1964 JRJ (Bob Jackson), 1973 Wes Mason, 1974 Raleigh Gran Sport, 1986 Schwinn High Sierra, 2000ish Colian (Colin Laing), 2011 Dick Chafe, 2013 Velo Orange Pass Hunter