Hi TxDive: I fly the 5985 on rudder and 5625's on everything else for 3D planes, I am yet to try the 5955 so cannot coment on it's centering but do know the 5985 is better than the 56 series. Am yet to have a Hitech fail and I have a drawer full right down to HS55's on sub 16oz park flyers. Whatever you decide do not scrimp on servo's or the power supply for your airborne system.
You have a lot invested in the plane saving $200.00 at the end and posibly ending up with a failure does not make for a good day.
You have to have absoute confidence in your set up, if you feel that the JR servos are required do it. At the end of the day it's your time and money on the line not ours.

Go have fun Eric.