I currently have two twins. A GWS P-38 and a Hobico TwinStar.

In the P-38 the Castle Creations (CC) Thunderbird 18 Amp ESC's connect to a "Y" and plug into channel 3. These ESC's are good to parallel the BEC's, some others are not. The ESC's are in the nacelles and connect to a hand made 14 AWG "Y" to a 3S1P 2100 (6 min) or 3200 (11 min) LiPo.

The TwinStar is similar, CC HV45's are in the nacelles with the 4120 motors. A 12 AWG "Y" connects the ESC's the the 6S2P 4200mAh Lipo in the center of the plane. I use an LM2576-5.0 as a BEC, goto DigiKey.com for a datasheet.

I both the props counter rotate to make turning right and trimming easier.

It is important to test any new setup. I strap the plane down, run the motor(s) at 1/2 to 3/4 power while moving all the controls for 3 to 5 minutes. As I do this I keep checking the watts and amps, the temperature of the motors, ESC's, batteries and other parts. If everything is working correctly, no part should get hot. Anytime an ESC gets more than the slightest bit warm something is wrong, wrong timing, bad connection, motor and ESC don't like each other...