Hi all, I’m installing flangeless windows flush with exterior insulation. I’ll add a pre-assembled window trim with 3/4” extension to make up for the rain screen. How do I seal the connection between the trim and the window frame to keep water out (especially at the sill trim). Do folks usually add a bead of caulk here?  
The trim will be pre-finished with linseed oil, so I’m not sure if there a compatible caulks long term. 

Thanks!
Adam