That seems pretty reasonable. The original recipe for this layup called for at least 9oz of glass so sanding into the outermost layer wasn't a big deal. I probably will avoid sanding into my fabric - it was expensive and I'm not going to all this trouble just to sand it away

In reality, I will have to do a little blending at a few seams and I may throw a thin glaze coat over the whole thing but, I guess the point I am trying to make is, (is this back-pedaling?) the fill-coat step is minimized.