I have gone ahead and ordered some Freesole by McNett. Mostly because it seems to say it is for exactly the task in hand, but also because it cures through exposure to atmospheric moisture rather than just by solvent evaporation like Shoe Goo. I want to use a generous coating so that all the gaps are sealed and no water or dirt can get in and work its way under the sole. I was a bit concerned that the Shoe Goo that was in the middle of the sole might take a very long time for all the solvent to evaporate, and that if I stated wearing the boots again too soon, it could weaken the bond.
I have always believed that if you are going to fix something then the end result should be as good, if not better than than the original. A repair should last as long as the item fixed. It is tempting to just throw things away and buy new, but I believe that mending what we have and use may help make this old planet last a little longer. Glue is a tricky subject to understand and because of advertising hype, most of us have had the experience of glue letting us down. There is no product that can stick anything to anything in any circumstance. So thanks again for the help. I'll let you know how it goes...
Z