These are the specs on the Airtronics servos I'm looking at/considering. My only question is if they are a dual ball bearing or single. I'm guessing single from the price.

Rudder/elevator.. $30 each "standard size"
Airtronics 94846 High Torque BB Digital Servo • Gear Type: Metal Gear
• Motor Type: 3-Pole
• Weight: 51
• Speed (s/60d):
• 4.8V: 0.23
• 6.0V: 0.2
• Torque oz-in
• 4.8V: 107
• 6.0V: 136


For the Ailerons $17 each "mini size"
Airtronics 94813 Micro 18gDigital Metal Gear Servo
Specifications
• Metal Gear
• Motor Type: 3 Pole
• Weight: 19
• Speed (s/60d):
• 4.8V: 0.19
• 6.0V: 0.16
• Torque oz-in
• 4.8V: 50
• 6.0V: 54