Jonathan,
There are about 3 different joystick valves used in the last year or so.
One was a non-float valve, the other two were float types. The non-float valve functioned well regarding speed, but was missing the float function and some wouldn't work two-functions at once. When placed in the diagonal, the loader would drop.
The float valves were very touchy regarding boom drop, especially with a load. You have to be real careful if you want to lower the boom just a little bit. This was fixed in coordination with Ansung and Bondioli by installing an orifice at the valve in one of the lines. The first orifices had a single larger hole and they worked well. For some reason, they switched over to a double hole orifice with smaller holes. On paper that works better, but in the real world it is too slow. Drilling both holes out to 0.0625 - 0.068 has worked great for us. Buy an extra bit, they break easy when they are this tiny! The dealer will do it for you at no charge.
The three-point valve is for regulating the descent of the three-point, I don't think it would have a direct correlation to the loader speed, but I've not tested it with that in mind.