From that great video I'm seeing a couple of things.

First is that the builder/designer did a masterful job of keeping the weight down to the lower limits of what is acceptable for a model of this size. It shows in how easily and slowly the model achieves lift off and how slow it flies and the rather dainty way it touched down.

As for the stab angles it brings up the idea that is often tossed around that the best way to measure the wing to stab angular difference is to use the wing sections zero lift angle as the reference rather than the simple geometric center line. So if the full size and model use a cambered section then the stabilizer could well be sitting at the proper angle for flight even though the stab is at some negative angle to the wing airfoil's geometric center line.

In any event daRock's explanation given above is what will happen in flight. You will set the CG to some location that you feel is valid then you'll end up trimming the elevator to let the model achieve level flight at some power setting. The final angle of the elevator trim will be set solely by the CG position and chosen/required flight speed to fly level.

The manner in how the model responds to changes in power or flying speed due to diving, etc will be set by the CG location and the elevator trim location that is associated with that CG location. If the model seems to respond too strongly to changes in speed due to diving or adding power then the best response is to shift the CG rearward by some amount and re-set the elevator trim to regain level flight at the cruise power setting. The resulting change in wing to stabilizer angle will make the model less pitch stable. But as with so many things in life too much is often just as bad as too little. The key is to find the happy middle ground.

So all in all if you intend to use the scale airfoil and it is a cambered one then you might want to stick with the scale wing to stabilizer angles. But on the other hand if you go to a 0-0 geometric setup that would hardly be a bad thing either. In the end you might end up with a little down trim for level flight or you may not.

And finally a little background on stabilizer lift. Whether or not a stab on any particular model is a lifting stab is set solely by the CG location. It doesn't matter if you give the stab a positive angle of incidence or give it a lifting airfoil or stick it on the end of a long tail moment. It's still the CG location that determines if the stabilizer is lifting or not. Almost all full size aircraft have the CG range ahead of the 25%MAC point. As such the stabs on them are always lifting negatively to counteract the torque of the CG locatoin trying to pitch the aircraft down. On the other hand most of our models and some specific full size aircraft have their CG ranges behind the wing's 25% MAC position by some amount. On these the stab is always lifting upwards to prevent the wing from wanting to pitch up.

The reason that this is still a stable setup is that the aircraft has an overall planform center of lift (that's likely the wrong description but it's the best I can come up with) that we call the neutral point or NP. A design which is balanced at the NP will show signs of being neutrally stable. That is, you can put it into any attitude and assumging it has enough thrust to not stall it will stay in that attitude until it hits something. But most designs are set up to have the CG be located at some small distance ahead of the NP in order to be positively pitch stable.

So you can actually have some extremes such as found on old 50's era free flight models where the large stabilizer on the long tail resulted in the NP being at or even slightly behind the wing's trailing edge. And the desireable CG location was thus sitting at or just a hair ahead of the wing's trailing edge.

Or look at a canard or tandem wing setup. Such planforms are still analyzed to determine the NP by considering the foreplane as the "wing" and the rearplane as the "stabilzer". The resulting NP location on a canard ends up back near the leading edge of the rearplane. In effect the proper way to look at such a planform is that it's a "conventional" layout that has a really small wing and a really big stabilizer that happens to be strongly lifting because of the very rearward CG location.