Doweling ANYthing to 'sacred' surfaces of a machine tool is very, no extremely, uncommon. Cylindrical dowels need clearance to install and remove, introducing undesired error. Tapered pull dowels would be better, but still über-unconventional. The other problem with doweling relegates all the gib wear to one zone, far better usage alternates vise placement on what ever schedule you deem fit.
If one cannot dial a vise in 3-4 passes with an indicator, they need more practice, and perhaps a change in technique. Clamp a long straight bar in the vise and view it lengthwise in accordance with the table slots. I do this when the material is not smooth enough for indicating. The laser level method isn't a bad starting point, but a laser pointer won't work. They are not intentionally centered in their body.
But the following is my everyday go-to, several decades worth.
Start with the indicator midway on fixed jaw, move Y to achieve some indicator + & - travel. Any line should be a convenient zero, just because it's marked '0' is not fully relevant. Any displacement of the needle moving X will be readily apparent of which direction is angled from table travel. One stud can be lightly snugged, tap in the vise body to lessen the needle travel as you move towards end of jaw. By the time you arrive, the jaw reading and starting zero should be very close. I continually get a vise .0001 in 1 1/2 passes.