Brownells by a wide margin. And also get the set of thin blades. Properly grinding tips is fine but for me its difficult to achieve perfectly parallel sides with equal thickness side to side. For grinding I have a diamond wheel that is chucked in my drill press and I can cinch a turn screw into a small milling vice and sliding it on the drill press table I can maintain a perfectly flat head. Still difficult though.
PS: I think one of the main reasons we see screw heads messed up is the slots were not carefully and completely cleaned out before trying to turn them. And a lot of the hundred year old gook in a slot is rock hard. An Exacto blade will clean them up nicely. I usually use a thin piece of brass sheet Ive cut into a V point to dig it out.
