I found that leaving out the traveller fully and then leaving out the sheets helps the most when about to right the cat. I never had any succes with the mainsheet tight or traveller tight. I used to right Prindle 16 solo this way; very comparable to your boat. Also straighten yourself out fully when hanging almost perfectly horinzontal onthe righting line. A few inches above water and climb up slowly in the line right before your butt hits the water. Imagine you're at the marines and some drill officer is giving you a hard time. Hang straight as a plank and only inches of the water during the whole rightin manouvre. To many beginners hang of the righting rope the wrong way.

Best learning is to find a catsailor with some experience close by enough and sail with him for about 1 or two hours running through all the motions including righting.

Wouter