I use the following method..If anyone has any pointers to this method that would be appreciated
1. Start with the width of your bow just a bit oversize on the areas you are applying overlays. Once the process is complete, any rounding of th edges will be mitigated upon your finished width. Tape off the area to be overlayed, sand with 36 grit to really score the glass, then 80 grit to ensure the whole area is roughened. Your tape will serve to keep the sandpaper off the glass where you dont want to sand.
2. Clean with acetone. Using smooth on glue them on. I do not thin anything before glueing on, but make sure I have even clamping preasure over the entire surface especcially the ends.
3. After full epoxy cure, take the overlays to the drum sander, with 120 grit start to sand the overlays until you are about .020 from your glass. Have to be careful on this part.
4. Take it to the workbench, using a round file sand the overlays until the end is about as thin as the tape you put on in step 1. Remove the tape and you should have a thin ledge to sand off.
5. Use 80 grit paper and sand that final ledge. Just as Marty said dont be afraid to sand the glass. If you go slow it will be a smooth transition in no time.
6. I usually take CA glue and cover the area just sanded. I feel as if this hardens up any open spots and fills anything in and for some reason just feels right. Then I usually move on, finish the rest of the bow and then I hit this area with 120, then 220 upon final finishing.
Should make for a smooth even transition.