Gphil, asking questions is what this forum is all about. If anyone tells you to stop, they are the one with the problem.
Getting back to your servo question, most planes, up to a sport 60, can be flown with standard servos. When you go larger than the sport 60, the servos may need to be more powerful to prevent overloading and the subsequent failure. As far as using mixed systems with one brand receiver to another brand of servo, this is done all the time. Some servos will require the connectors to be modified to fit or pins reordered but in can be done. Never try to modify a receiver to work with a servo. Changing anything inside of the receiver or transmitter case is a violation of FCC rules and, if you're caught, can cost you some cash due to fines and/or having to replace radio gear.