Mark.
You can use Shelac or just about anything to seal it, the big trick is to give oily wood a good washing in Acetone to get as much of the oil out as you can.
I am thinking about using some Minwax Antique Oil Finish on the next bow to see how that works on an oily wood.
That is if I can find it in a hardware shop down here.
Tana.
He better let you shoot it