I have used stick, mig, and tig to weld on bolt handles. Tig is wonderful for this use and all welding on firearms. The down side is it is the most expensive to get set up for.
This example is EXCELLENT work. Longshot have you tried Brownells high nickel welding rod as a filler? It works great for me.
I think this knob configuration is great for Canadian hunting conditions. As far as looks go, I find the better looking a bolt handle is, the harder it is to grip with gloves in the cold. My favorite for looks are the butterknife style handles. These are hard to manipulate with gloves on, to say the least.