Hey Avi, welcome to electric! (I myself am kinda slowly leaving the nitro scene)
I can't answer alot but I think in general it seems that alot of electrics run a head speed close to 2000rpm. I run a T-rex 450xl, not sure of the headspeed, but I do some neighborhood hovering at about 6deg pitch. I use the hov. pitch function on my radio to adjust necessary headspeed to keep electronics as cool as possible. A good guide line (if your just doing light flying like forward or hovering) is a warm battery, warmer esc, and a motor thats getting close to hot but you should be able to keep your fingers on it. Those are my guide lines and in general I've found that it works for all flying once I've got hover figured out. And yes, there are ESCs with governor functions on them. Here's a 20amp esc from telebee that you might look at ($26 for a 20amp and $28 for a 25amp at helihobby.)