Fin box install and glassing

I have a 10" fin box that has a flange around the top and ra ised lip around the slot.
Once the box is installed, how do I handle the glassing,
Just glass over the lip and then sand flush, or sand the lip flush and then glass over the top as you would a normal flat top box?

A pic would be good, but I assume its something like this. The top of the flange should be flush with the surface of the board before glassing. Glass over the flange and up to the lip - I just cut the glass at the lip with a sharp blade as I’m glassing. Maybe others have a different way. Anyway, once the bottom is glassed with however many layers you’re using in the tail area, you can sand the raised lip flush with the level of the glass

Yep, that’s the box, your method makes sense so that’s the way I’ll go.