To answer the mount question, the EQ5 is the basic model, HEQ5 is the heavy duty and the pro has the additional go-to system installed.
I believe the EQ, HEQ and pro related to all the models.
Higher the number the heavier the mount and the more weight it can support e.g 6 can support more weight than the 5
Still new to this whole thing so maybe someone can give you the specs etc of each mount if required.