epoxy is the way to go, but you will have to work fast. I mixed almost a gallon per stringer (epoxy plus filler). Trick is to put epoxy in the fridge the night before so its cool, mix it with a paddle mixer and put in fillers. I then put it into empty caulk tubes to run nice fat beads down the stringers.
I actually used 3 gallons of gel magic epoxy for the stringer bedding on my 23. It was some old stock that no longer would hold shape - turns runny. I had to add a lot of silica and wood flour to the gelmgic to get it to hold a bead. Even new gelmagic will not hold more than a tiny bead. GM is great for tight fitting joints, but for bedding down stingers it will not stack high enough without mixing in fillers, and if your going to have to mix in fillers anyway, then just start in with an epoxy that costs half as much
