Hi Dave,
When I do mine with vertical strips I like to sand the strips first before the fillet. Then form the fillet with thickened epoxy and install the bias cut glass right into the fresh epoxy fillet.. This forms a great bond between fillet and glass. Be sure to cut the glass on a bias, so the strands are running on a 45. This helps the glass to make the bend at the fillet plus all the strands are adding to the strength of the joint.
If you have Nick's first book Strip Built Kayak It is covered in great detail in the book. If you don't have the book it's a must have.
Good luck,
Clayton Plunkett