Jantex is to be avoided at all costs! It was never intended to be a replacement for glue, only to tighten up a stretched out but still useful tire, but only when used in addition to glue. I made that mistake as a rookie in 1973, thinking this would be a lot less messy than glue. Worked fine until I punctured in some gravel at 40 mph down a hill and the front tire came right off the rim and wrapped itself around the wheel. I went skittering along on the rim for a bit, the fell and slid on my side for an interminably long time. Scrapes from head to toe and the bike didn't fare well either. I won't use the tufo stuff for the same reason. Use glue, and a couple good layers at least. Put the tire on when the second layer is still sticky so that it will have some chance of impregnating the base tape on the tire.
Bob Freeman
Seattle