RE: Great Planes Extra 300SP help
As a suggestion, before I finalize mounting locations for batteries, switches, servos and such, I'll temporarily mount them in the desired locations and do a preliminary balance check. This will at least let you know your options before permanently mounting anything. Unless you use the exact equipment recommendations from the manufacturer, you can't go off of their mounting recommendations 100%. Even small differences in servo weight can mean a lot with balance because of the tail moment. Many airplanes have about a 4-5:1 nose to tail ratio. For every ounce of weight that's added to the tail, you'd have to add 4-5 ounces to the nose to offset. So, you have to be very mindful of servo weight for tail mounted servos.