I used an insulation from A/C Spruce which is probably not as good as Zetex
but gluing it down is the issue here not the material.  I have used several
types of cowl/turbo/exhaust insulation over the years.  I have always used
"pro seal" as the glue and as the edge binder.  It works very well.
Pro-seal type tank sealants are listed in the A/C Spruce catalog on page
304.  The cartridge types are easiest to use but require you purchase the
dispensing gun.  No, your home construction caulk gun won't work unless
highly modified.  Not worth the effort.  Real penny pinchers will order the
quart size and go thru the weighing/mixing/getting it out of your hair
drill.  Scissors work best on the hair should you inadvertently get it
there.  Many pairs of latex or nitrile gloves are a must!  The good news is
it will never peel off or part at the edges and it looks professional as
heck.  Any type of tank sealant will work (should you be able to find some
out of date at your local repair station) but the general window sealant
works well.  I would not recommend the low adhesion type.  I am also using
it to seal my thru the fuselage wire bungs for pressurization.  Again, hope
you won't ever want to remove the wings cause it is pretty hard to pick out
of a bundle.  No chance of a leak, tho.
Walter Dodson  IV-P  100%  First flight Sunday AM