fastener thread pitch choice

Hi Everyone,
are fine thread 10-32 screws better than 10-24 screws for fasteneing step motors on to aluminum machine frame or aluminum gearheads? Can the 10-32 screw be torqued to the same value as a 10-24 thread? Will the screws hold the joint together as tightly? If a steel screw threads into an aluminum thread should the threads be coated with an anti sieze compound? I hope everyone has a great summer.
thanks,
Denis