aaronwhite

I do this pretty much exclusively when I fly, but usually what I'll do is make sure I've got enough altitude to work with. There's always going to be a bit of a problem, since your controls aren't where George's will be when you're going from the front seat to the back, but as long as you've got enough altitude, you should be okay.
The thing I've realized helps with switching to the front seat for me (and is just good practice in general) is to get as close to a "hands off" hover as you can in the back seat before switching to the front. It takes some time to get comfortable with the ALT/ATT holds, but I've been practicing getting into a hover with them, and it's made it a lot easier to switch seats.
Generally, I'll fly myself to the location I want to attack from, get behind cover and get my airspeed below 5 and steady my collective to hold altitude, and then I'll engage the altitude and attitude hold and give the helicopter a few moments to steady itself. Once that happens, I can switch to the front seat, and there's usually a little movement, and I often have to bring up the George menu to get him to point the helicopter back where I had it facing, but after that, it's pretty solid. Once I'm done, I'll switch back to the rear seat, at which point I usually start to instantly bring the collective up and add some rudder to start turning and gain airspeed again.

Assuming it's all mapped correctly, it sounds like you might have the trim mode that doesn't respond to cyclic movement until you've fully centered it. This means any time you click the trim, until you fully center the stick, other control changes will be ignored. This can be useful for people, but if your joystick has any play in the center axis, it can sometimes be tough to fully center your stick in the heat of the moment, leading to your controls being "locked".
You might check that out, and try the other trim mode that instantly trim and requires you to physically adjust for the new trim position.