My question exactly, and I asked it a while ago, and got answers all over the place, but the concensus seemed to be in the inch and 1/4 or less for sure, and above that a little less than a quarter inch - but if your measurement would put the guide, say, an inch and 3/4, you could get away with fudging on your measurements and put it a bit over a 1/4 inch closer to the ferrule and wrap together - maybe adjust your other measurements a tiny bit.