Sean,
Wilson's "Guide to Rigging Braid, Dacron and Gelspun Lines" does not address specifically dacron to gelspun. However for GSP to GSP he recommends 40 turn biminis loop to loop with ten fold cat's paw.
My opinion is loop to loop will work well with GSP/dacron, using multiple passes through a loop to spread the load [cat's paw].
Sounds like you're after bigguns!