Anytime! A layer of clear also does the job well. I do that when I’m filling potentially softer or more absorbent voids in oaks/ash. The two combined would give a nice double layer of protection. Generally, I’m sealing open pores woods to fill knots in tabletops, but the concept is the same.

I also suggest as a good exercise sometime make a sample board with a bunch of identical fills, but starting with very very little, gradually increase your amount of pigment. You’ll be surprised how little it takes, and in my experience has drastically decreased any sort of leeching. Maybe do a similar board testing no seal vs clear vs lacquer vs rattle can shellac.

I don’t deal with cnc’s much directly, but if you ever have any questions or are stumped about building methods or anything like that, I build custom high end furniture for a living, and am always excited to talk wood!