I was able to get my grain filling done a couple days ago. I had never grained filled like this before, so it was a new experience but I am pleased with how it went. If I do another build at some point, I would thin out the grain filler to make it an easier application. I am planning to do some light sanding on the body this weekend, as recommended by the product I used for after grain fill application.
My next steps this weekend will be to shape the headstock, and then start spraying my sand sealer, and possibly primer, depending on how things go.