I have been setting up my large planes for 4 or 5 years on the tail like the picture. I have never had any issues with the connectors coming out or even appearing to be backing out. I use a similar set up for the main wings.i will do the heat shrink for the rudder servos, but the stab servos need to be able to where i can remove the stabs for transport.
Cam if you have duel servos on each stab and you want to be able to remove them Chad @ taildraggerrc has these....I use them on my wings but not on my stabs since I never remove my stabs for transport. They lock in good and you never have to worry about them coming loose during flight...
I use nylon wire ties that have a square flange molded in for affixing to something secure and then use the plastic servo connector retainers.View attachment 4660