For those in the building trades, I think the technical
term for "gasket seal" is,

Poly Foam Sill Seal Gasket
with a product description here,
http://building.dow.com/na/en/produc...wmsillseal.htm

We often use 3.5" x 50' , rolls for many applications,
(it's usual only an 1/8" thick cuz we're really good :-).

Would anyone kindly suggest how to glue gasket seal
to dry spruce/pine?

We've been stapling, but I'd like something more elegant.
Thanks
Ken