Well, I finally got a result I could live with in applying satin finish Minwax Spar Urethane. I left the original ink lettering and blended it in as well as possible.
The first two coats went on like corn syrup and dried badly, leaving drips and runs. I sanded them back and tried a 60/40 mix with mineral spirits and applied it with old, well laundered (and lint free) cotton. Each application went on thin and I worked out a few runs each time with 400 grit and OOOO steel wool. Last three coats were 80/20 thinned and applied with a foam brush.
Came out pretty good. I radiused the shelf (it was flat) and you can see one spot just above the thumb groove where I didn't blend in with the old finish very well.
I wiped the limbs with linseed oil and it darkened the minor scratches vey well.
(http://img.photobucket.com/albums/v169/Stumpkiller/Bowhunting/HPIM1897.jpg)
(http://img.photobucket.com/albums/v169/Stumpkiller/Bowhunting/HPIM1901.jpg)
(http://img.photobucket.com/albums/v169/Stumpkiller/Bowhunting/HPIM1899.jpg)
(http://img.photobucket.com/albums/v169/Stumpkiller/Bowhunting/HPIM1902.jpg)
You can see the original ridge line of the flat shelf in the below image.
(http://img.photobucket.com/albums/v169/Stumpkiller/Bowhunting/HPIM1898.jpg)
(http://img.photobucket.com/albums/v169/Stumpkiller/Bowhunting/HPIM1903.jpg)
Sorry, no before images - but picture a 1969 bow that had been used and chipped and refinished with a glossy finish heavy on brush strokes.