For you 'battery share device' you can use a Fromeco Wolverine switch so no need for 2 separate mechanical switches. The switch includes 2 charge receptacles. The 645's are too weak for 30%, you want at least 180oz servos for 3D, for the rest everything looks OK.

For 30% personally I prefer a single switch like the UltraSwitch II http://electrodynam.com/rc/ultraswit...html#USWReview and a decent battery. I've never had a single glitch while I have seen many planes go down with their 'redundant' setups.

Ultra Switch II HD-R2 $29.95