John Betmanis wrote Tires are glued to rims using a very agressive solvent-based glue. The base tape is glued on using base tape cement, which I can't find anymore but I've been told it's the same as Jevelot Tire Life.
After speaking with the father of a friend of mine who repaired lots of tubulars (or as we called them ,singles) in the 70's and 80's the glue that was used was the same stuff that carpet layers used to join pieces of carpet with a backing strip.It was a white runny latex glue.I am not sure if it is still used for that purpose but it might be worth asking some questions at your local carpet layers Geoff Duke Melbourne Australia