I like to use a razor blade to cut it down some, then like a scraper.
The taper rate of the overlay is key too, you do the last sanding with 220 grit and then you have messed up the nice crisp line. I have a good many taper sleds for overlays. .040/.050 per inch works good for me.
Let's say a .020 per inch, it's .010 @ a 1/2" and .005 @ a 1/4"--you will sand threw that a screw it up.
So go steeper to glue it on, then hand sand it shallower.
Left side glue on, right side sand it back where you want it.
I like to use a 6" ruler and wrap sand paper around it.
You have to make sure you are pressing down the ends of the overlays also at glue up.
Humming bird bows used smooth-on as a overlay, over the ends to make a smooth transition but you can get air bubbles in it, not good, putting you mix in a small vacuum chamber before applying, could fix that, I've never tried it.