welding/rod recommendations

Hate to see time and effort wasted when it comes to such things. How many times do you want to weld them back on? What you propose can be done but is no place for 60xx series rods, cold joints and non full depth welds. The alloys used for cutting edges and corner bits vary a lot but at the least they will be T-1, sometimes sold as AR 360. More likely they are 400 hardox or better.   You need to full depth vee the joint (yes, to a point) and also spread the parts a bit, we alwys use rod stubs with the flux knocked off. Properly done there will be weld all the way through, not just laid on top.  Like Coke said heat the parts first. Lacking experiance or a temple stick to guide you if the heat from the parts isn't a bit uncomfortable  while welding they are not hot enough. As for rod I like 11018 although 7018 will work if the particular alloys involved are not too tough. If AC is all you have then you are stuck with the AC variant of 7018,  You will sometimes see 60XX series rod recomended for root passes but I have never seen them used in the field, low hydrogen all the way up. When welding if you hear the "tink" of cracking you might as well stop because the are going to break off at the first rock. Have not found cooling to be critical or any post welding treatment except one time on a drag bucket lip that I suspect was some type of casting. Good luck.