I didn't want to say anything until I had tried it myself, but since you use MRP lacquers in your builds, I came up with an excellent way of painting the markings on instrument dials. I tried the idea I had been thinking of, and got really good results with it this weekend.
I'm painting a 1/48 Monogram F-100D instrument panel, so what I did was to start by putting my usual decanted Tamiya Grey Surface Primer on it. After that was ready for paint (about 2 hours later), I sprayed the whole instrument panel with MRP-004 White lacquer.
After the MRP lacquer was cured, I used some Bob Dively Liquid Mask and applied that to fill the dial face of each instrument. Then I sprayed MRP-100 Dark Gull Grey over the entire panel.
Once the dark gull grey was cured, I used the same liquid mask to mask off all of the areas of the panel that were going to stay grey. After that, I sprayed MRP-171 Super Matt Black onto the whole panel.
When I took the mask off, I now had black instruments with a grey panel. As you're aware, liquid mask doesn't give you very crisp edges, so I'll touch those up with the Testors square bottle flat black enamel that I'm going to use in the next step.
Interestingly, the liquid mask I used to cover the grey areas of the panel didn't join with the mask that I had previously applied to the instrument dial faces, so I used my trusty Tamiya scribe, canned air, and my cheap electric toothbrush to dislodge the mask from all of the dial faces. A soak in plain water afterward, along with more of the toothbrush, got all of the tiny remnants of liquid mask off of it.
I now had nice, white faces for all of my instruments, so now I just have to turn them black. This time though, I used the Testors square bottle flat black to blacken the dial faces.
Didn't have to wait long at all (maybe 20 minutes) for the next step, since a full cure of the enamel at this point isn't necessarily a desirable trait. Then I took one of my new Tamiya extra fine swabs (just got them from Tamiya...love them already), dipped it in mineral spirits, rolled the swab on a paper towel to wring most of the mineral spirits out of it to leave it barely damp. Then, it was just a matter of lightly wiping the swab around in each instrument face...which left pure white, sharply-defined, instrument markings on black backgrounds.
Now I just have to go back with the Testors and touch up the edges of the black area that are still grey due to the kind of ragged edges that liquid maskers leave behind. Once that is done, I'll put an MRP semi-matt clear coat on the whole panel, and follow up with a little, thin drop of Bondic in each instrument to simulate glass.
I'll post pics of the finished product, but I'm really happy with the result so far. Gonna use this technique on the rest of the aircraft I have in my Monogram Century Series lineup. Took only an hour or two total work time to get it done.