the oils in the rosewood will not let the spar urethane dry, same when using cocobolo. I used 025 cocobolo veneers in my first bow and did not seal the limb edges..the limb edges stayed tacky even after 2 weeks so I had to sand them down, seal with thin super glue and refinish, no problems after that, finish dried quickly. I am using Minwax Spar Urethane Satin for my finish. If you do some research you will find a finish that may not need the sealing.