Hello Sandor,
Nice video of the Raven. Again congratulations on putting everything together and getting her up in the air; I know that this is no easy task. What kind of flight times are you getting? Also have you done any acro experimentation?
As far as the 28/10 prop size goes this a target that we hope to achieve. I am always pushing to try to have scale props.

on my aircraft. I did have a friend in southern CA. that was successful in turning a 28/10 but this was on the bench and not in the airframe.
Again congrats on the Raven flights
Take care
David