This may be late to be of help to you, but i epoxied white oak spacers on I-beam type cross beams for a Wharram Tiki 21. i sailed it for about 10 years without any delamination problems. Cross beams on a catamaran do undergo a significant amount of stress from hulls that are designed to attach with flexability. i ran into a lock wall one time that split off a piece of Doug Fir from the beam, but the oak stayed solid as I recall. i used West System and bronze fasteners.