The AOI of the tail isn't going to have much effect once you've got your pitch trimmed.

If the AOI is close to optimum, the elevator trim will be so close to zero deflection you won't be able to see it.

If it's off one way or the other, you will be able to see elevator deflection at rest when you're close to the model. You'll basically have a cambered airfoil back there. It'll produce the lift needed, in the direction required, to keep the wing at it's AOA at your usual flying speed.

Most of our models don't get pitch twitchy from having the tail AOI inefficiently set. And most are quite tame once we've got the CG in the right place and our pitch trim adjusted. The elevator might not be perfectly in line with the stab, but the model usually couldn't care less what it looks like back there.

How those planes in the videos took off were more apt a function of too quick a throttle application, their power loading, their CG location, and how accurately the pilot worked the sticks.

BTW, where did you find the AOI info on that airplane? That kind of info is really hard to come by in the usual sources available to modelers.