Rather than call it overhoning on the spine I'd call it uneven blade wear. If you get an edge that needs a lot of correction you'll get spine wear if you don't use tape. An edge that is good to start with, and the relationship between edge and spine are parallel, you won't get much wear, and what you do get will be even between the two, if you do it right.

I've done it both ways, with and without tape, and now I always use tape. If I was as proficient as Lynn Abrams I could probably get by without it, but it is like my having the same bicycle that Lance won the Tour with ........ I still max out at 21 mph.

Dremels can clean/polish, but in unskilled hands they can wreck a razor at worst, and leave uneven polishing marks at best. Skilled hands can do pretty good with them, but AFAIC a buffer is the better option.