Help on screws

I'm working on my first kit, a DDR-1. I want to put impala horn scales on it, but this means a thickness of close to 1/4 inch for each scale, which is way too thick for the screws included with the kit. I could just epoxy the scale to the liners, I suppose, but I'd rather use the screws.

I see that I can order longer screws, but I don't know what size to order. The instructions don't identify the screws in the kit by size, so I don't know if I need a 1-72 or a 2-56 or something else.

Hi
The screws can be replaced 1-72 screws . We have them on the site in a longer length.