Errrrrr.....what are you exactly trying to do ?
You say you want to change the inlays...from what to what, as i'm trying to think what you're planning to do with all this sawdust ?
Are you:
1)... wanting to remove the old inlays and, using sawdust, try to make the board look as if it has no position markers at all.
2)... wanting to remove blocks or crowns and replace them with dots, hence the sawdust to fill in the larger cavity's
3)... remove some cheap plastic or MOToiletseat and replace them with MOP or Abalone and want to raise the bed as the existing inlays are deeper than the new material you want to inlay.
In answer to some of your questions:
Drilling: most inlay material is around 1mm > 1.5mm thick so you dont have to go very deep at all. If you have a brad point bit use that, the smaller the better until you get the first one out and see what you're up against. Use a hand drill if available as a power drill will be through to the rod in no time . Once you've broken through the middle of the first one use whatever's at hand to gouge the remainder out....carefully.
Sawdust: All woods will, with the exception of ebony, change colour when their dust is mixed with glue, they tend to go lighter or darker. Ebony still changes colour (tends to go darker) but it's much less noticable than with other woods.
Superglue: Use the thinnest you can get so it will seep into the dust uniformly, don't use epoxy unless you're doing something big like the full headstock or the back of a banjo.
Precautions: Don't drill through the neck or your fingers
Hope this helps,
Jem
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I just want to take out the old inlays and put new ones in. I think the old ones ar elike white clay and the new ones will be mother of pearl or something. Frankly I cant even see why I would need sawdust because they both will be circles, and you won't be able to see the sawdust or glue, if i did it right.