Here's how I would do it.
First borrow a big mirror from your wife.
Put the Prather gauge in front of the mirror.
While looking at the image of the gauge in the mirror, put on the pusher prop.
![Grin ;D](https://stunthanger.com/smf/Smileys/classic/grin.gif)
On a serious note
![n1 n1](https://stunthanger.com/smf/Smileys/classic/nono.gif)
, why repitch? There is a lot of flexibility in the electric system to retune the rpm to match the flying characteristics. So if my 12-6 was too fast, I would just dial down the rpm, and if too slow, dial it up---within reason of course.