Thanks a lot to you guys, all your tips are really helpful, I really appreciate that.
I managed to participate in some more races since my original post, so far results were mixed but overall much better, we even managed to finish first in one "all boats regatta" race on our lake.
Bridle fly came out to be quite handy, thanks to gregP19 . Now I see that P19 is a great boat indeed ,she has a lot of potential and it is just a matter of right handling and experience.
I've noticed that combined weight is really important but it is not all. we were the heaviest team again when took first place in one race. thanks to correct weight distribution according to Caitus and Andrew's tips. Remarkable that again a lot of H16 were singlehanded but only one H16 with 2 adults + 1 kid crew !!,
nevertheless exactly that particular hobie finished first in 2 races and passed the others singlehanded H16 . wind's speed was probably about from 5 to 9 mph .
In some other 2 races every cat was singlehanded including me; so I finished second and one time I came first .
As far as I see it right now that the guy who wins is the guy that makes less mistakes. (and sometimes forces the others to make them )