These guides are great and have provided so much great info, including this one. However, I struggled with finding a good finishing putty to cover pin holes and tiny scratches in primer/basecoat. I wanted something that could be easily and quickly applied, sanded and re-topped without issue... I have heard great things about a product called Evercoat Clear Sand, but I needed something I could purchase locally and quickly.
Well, I picked up a few tubes of 3M Bondo Glazing Spot Putty, and I am very impressed with the final results. I used a credit card to apply a feather coat on top of my kilz primer, let dry 45 minutes, and then sanded. It's nice that it's a 1 part system so no hardener/mixing required. It's extremely easy to sand, and I was able to apply a further topcoat immediately after the initial dry time. it easily filled pin holes and minor abrasions that I missed with wood filler applied prior to the base primer.