Did a bit more reading and even with CA glue it takes a minute or two to fully cure.
As to how... I was referring to one of these clamps:
Attachment 45590
I haven't done it for fixing frets, but I have done something similar to clamp a neck. Here's my idea...
In the pic, the clamp has two yellow pads. I would leave one in place for the bottom of the neck. On the top I would pull off the yellow pad and make sure the plastic was very flat. I'd make a caul out of a piece of hardwood that was about 1/2 inch thick, 1/2 inch tall, and a little wider than the fretboard. I would would put a radius on one of the 1/2 inch sides. I'd use double sticky tape to stick the flat side of the caul to the non-padded side of the clamp.
The trick would be making the radius. I have done this before to make cauls for clamping the neck, and something similar to make pickup rings that matched the radius of an archtop guitar. Here's how I made clamping cauls:
I have a 12 inch radius block (which is the radius of all PB necks and most of the "radius unspecified" necks you find on the internet). With the radius block I would put a radius on a piece of scrap wood. Softwood is fine for this part. Once I have a radius on the scrap wood, I slap a piece of sandpaper on it and use it to put a reverse radius on my hardwood caul. Not fast or elegant, but I am guessing it would work to fix a few frets.