Sadly the experiment didn't turn out to have a big effect.
After a lot of fine tuning it might give a little bit more then the current short stroke motor, but not enough to make a real impact in the 2stroke dominated 50cc class. So I'm thinking of quitting the 50cc altogether to focus on my RSC90 and maybe a CB72 that I've been trying for the last two events.
For now the 50cc has been converted back into a short stroke, with some minor adjustments to the head, valves and camtiming to get power at higher revs.
Next weekend is the Honda-day with a dyno, lets see what the little 50 has to give.