Now that I've sewn the trad kilt pleats...how do I correctly eliminate the bulk?

[Barb T]

For the kilt I made my son, I used a worn out pair of jeans for the interfacing.

Just as an aside, I don't recommend this for a trad kilt. You're much better off investing a few $$ in true hair canvas, which is less flexible in one direction than another and _much_ easier to stitch.