I used to repair plastics (and leather and vinyl) as a profession and both the super glue+ sanding and the heat methods are approved. Though, I used to melt in new plastic when using the heat method, but try a little heat first to help relax the stressed plastic and if it doesn't "come back" enough for you then let it cool and do the super glue method. Let it cool because heat and superglue don't mix...it creates a vapor that is NOT fun to get in your eye, and probably not a good idea to breathe in, so just work with cold plastic when using super glue...and don't try to heat super glue up.
I'm newer to the sport and don't play in tourneys yet, so I'm curious; if you heat the plastic up and don't use super glue, would it still be legal?
And as to dings adding more glide, I read that the smaller ones create pits of air that blah science blah more glide. But something that size is probably too big and will create drag, more than likely.