Mike,
The ballends that you need are 3.85mm in diameter, Microheli has them, they come in packs of 5. The screw that holds them to whatever you use them on, doesn't have a nut (so secure'em good). The description doesn't say what size socket head cap screw they use, but I'm almost sure it's 1.5mm x 0.35mm that what size I made the stud on mine, so it would fit the stock servo horn.
I also 2nd the use of the plastic blades from HD, they're pretty darn tough, even bad dings in the blades can be trued up with a few strokes of a file, rebalance them & your good to go. Have you tried the "glow-in-the-dark" white blades from HD? I prefer there look during daylight hours, but the "slight" glow of them in the dark, on the kitchen table is cool too!

Rick