I'm not sure how the A-cat handle it but I found when singlehanding my F16 (also low on momentum) that when I move over too soon as the skipper that I kill boat speed in a tack. Pretty much you want to do sort of a roll tack in these big winds. And yes that can get a bit hairy.

Look at it from this perspective. The outward hull mast arc through the tack at speed while the inward hull slows down. If you move to soon over as the crew then you body mass will have to be accellerated from slow to fast in order to complete the corner. The energy required to do this has to come out of the momentum of the boat as the sails are not providing anyd drive at that point. Taking this energy will slow down the craft through the turn increasing the time needed to make the turn in which the rig ca not provide sail drive but the overall drag can sap more speed. In affect you only get deeper and deeper stuck at low speeds.

Now if you roll tack then the lee hull with your body mass on it will slow down the most while the light outer hull will easily swing about. When passed through the wind the sails will draw a little bit again and then you can move over and complete the turn before capsizing.

I hope this makes sense.

Wouter