I sharpen my own blades too. When I bought a new set I made a tracing of the original so I could compare every few sharpenings that I was maintaining a shape similar to original.
For balancing I use the blade balancer thatguy mentions. It is cone shaped with stepped ledges, sits atop a pin mounted to a stand, and the blade center hole sits in the appropriate sized cone ledge. I set it on a level work surface and use a board "feeler gauge" to compare one side to the other (distance from work surface to blade tip).
I don't cross weigh one blade to the next, meaning I don't make each one the same weight, only that it is balanced by itself.
For a small out of balance I sharpen the heavy side more. For big out-of-balance you can grind a notch on the backside of the blade with an "L" head grinder to remove more weight faster but I've not needed to do this...yet.
I sharpen with a 7" "L" head grinder with the blade clamped in a vise. Then, if I have the time, I dress it with a flat file taking the last pass flat against the back side to remove the burr. Wear heavy leather gloves when filing! No, I have not cut myself, just a precaution that I don't.
For coating, there was a thread not long ago about a coating to get dirt to slide from a dump truck. Several of the posters had luck with a coating mentioned there when using it on their mowers. Sorry, can't remember the post or the coating name.