>>>What do you think, what would be better, how much righting moment will I gain!?


Increase in righting moment ;

Wider beams :

old = 130 kg * 0,5 * 2,5 mtr + 125 kg * (2,5 mtr + 1 mtr ) = 600 kgmtr
new = 130 * 0,5 * 2,75 + 125 * (2.75 + 1) = 648 kgmtr

Racks

old = 130 kg * 0,5 * 2,5 mtr + 125 kg * (2,5 mtr + 1 mtr ) = 600 kgmtr
new = 130 kg * 0,5 * 2,5 mtr + 125 kg * (2,5 mtr + 0,5 + 1 mtr) = 663 kgmtr

So you get more with 50 cm racks than you do with 25 cm extra beam. But I would always prefer wider beams over racks. Racks will be heavier overall and tend to catch waves at the leeward side. That is unless you make then curve up like the ones on hobie 17 but i don't think that those wings are very practical.

The downside of wider beams however is that you also increase the stresses in the beams as well as the resulting strains (stiffness) Alot can be compensated for by adjusting your dolphinstriker but some 25 cm extra width is alot. You need to get new beam which have a heavier layup to arrive back at your old stifness.

The advantage of racks is that they can easily be removed and you don't need a tilt trailer for your boat or disassemble it every time you transport it.

You have to decide what is prefered by you.

I hope this helps

Wouter