multires and subsurf best practice

so, how do people actually sculpt over 100k verts??? im using a multires mesh for some sculpting practice, but its not high enough res. my computer can’t handle another level of multires so im stuck at a bit of a crossroads.

Do i apply the lowest level of multires and get a ‘base’ mesh of 100k verts and then hide the parts i don’t want, or delete half the mesh and do a mirror reference (again apply multires)… do i retopo the mesh with a much better topography and apply a multires to the ‘nice’ mesh?

what are the better working habits to get past these kind of limits?

(and no, im not waiting for 2.5, theres always limitiations with software that need bypassing with some thought :D)