How to use a wood grain filler by Eric Gorges from A Craftsman Legacy

[@Mike-bh7sh]

Wondering if aqua coat cabinet filler would have issues if it is left thicker in areas? I'm looking for a grain filler that is fine being left on thicker in areas. The refinishing projects have opaque nitrocellulose lacquer finishes, and all I need is a flat, grain free surface. I don't like sanding dealers because if you end up leaving them on thick in areas, it really weakens the final finish. Thanks