It's easier to remove than add. When I'm in doubt it stays a little proud of the line and gets trimmed during the preglueing "analysis".

Sometimes this is a no brainer. I only ever got caught once cutting a set of elliptical ribs to plan only to find that they were as much as 1/16 short in a few cases. Now I'd leave them all an 1/8 to 3/16 long and trim during assembly. Same with the thickness at the trailing edge. It's easy to slightly sand the ribs down but it's a long haul to sand the whole trailing edge down. So the ribs get left long and fat for the last inch unless I'm doing a stack sanded rib block and I can compare the stock to the block.

I hate surprises....