Just an update, I made some sandles/shoes with the gorrilla tape, and couple self adhesive velcro patches and some chunks of rubber anti skid floor tape for the bottoms. I bought some cushion insoles from the drug store.
They've held up well for a week so far, no sign of tearing or splitting, They've done well for running the couple of times I was in the middle of the street when local traffic showed up. The anti skid soles work well and take the scuffing without problem.
Anyway I went around on the net. mcmaster has a little graph of duct tape adhesion and tensile strength, I also found info on permacel pro gaffers tape (therare two grades of gaffers tape pro and utility) and Nashua brand which is availablle locally.
What I found was that gorilla tape seems to be the stickiest and the strongest, with the caveat that it 1.88" and not 2", and you get 35 yards instead of 50 or 60 yards in a roll.
http://www.gorillatape.com/why.htm The price I paid is more than standard premium duct tape, but less the Permcel, but then you get more tape in a 60 yard permacel roll.
Permacel pro gaffers tape is next. The pro series doesn't come in as many colors as the utility grade, the specs are Tensile Strength - 48 lbs./inch,
Thickness - 12 mils, Adhesion To Steel - 60 oz. per inch
Following that is utility permacel and the nashus series, 357 which I formerly thought was decent tape, and a heap of lesser nashua grades down to ones only 25% as stong/sticky as the premium grades.
I find it interesting that there's "nuclear grade" duct tape, which by specs doesn't seem that special.
Also I found a tape with .002 Aluminum in it, seems cool though I don't know what I'd use it for.