PE Glue Question

I am working on the monogram A-26 .I purchased the Eduard PE set for it.The bomb bay set has replacement walls that require installation of the ribs on the walls.I usually apply the medium glue with a toothpick on things like boxes and sand off the excess on corners to fill gaps.On flat items,I use a micro brush and thin CA.Here's the problem.The ribs butt against the walls in a groove in the stringer detail of the wall.I'm affraid that if I use the micro brush and thin,I may get glue puddling in the stringer detail,but if I use the mediun CA I may get a glue showing up at the seam.This would be an almost impossible area to sand away any mistakes.Does anyone know of a way to apply the glue in a much more controlled manner.The PE set are beautiful and I don't want to screw them up.Any ideas would be greatly appreciated.
Thanks