I have not used the Dingotone products, but IMO the final grit depends on what type of finish is going to be applied.
For a stain/dye I would stop at a finer aggregate (say P 400) than if I was going to be applying a primer/paint finish (P240).

Using a stain/dye is going to raise the grain to some degree after applying to the timber. More or less dependant on whether it's water based, oil or alcohol based (water based is typically the most significant).

The raised timber fibres will need to be knocked back (lightly) with either a fine grade paper or synthetic sanding pad. I usually do it before each application of colour, or at very least before the clear coat is applied.

FWIW, Mahogany tends to be quite a porous timber and generally requires grain filling if going for a smooth high gloss finish. If not grain filled, it will require many many coats of clear top coat to achieve the same glossy result which can present its own set of problems. If you want a textured, rustic sort of look, then no problem.