I should start this by stating that I usually always drive our boats, both the SV and MV Watermelons. According to Peter, my job is "to cook and steer".
We put a feathering prop on SV Watermelon to reduce the vibration and pressure on the transmission more than to increase speed.
I'm not sure I understand you concern about easier reversing. Your present fixed prop makes reversing difficult in what way? Prop walk? Although we had slightly less prop walk with the feathering prop, we lost almost a knot of motoring speed in forward, and reversing required a bit more initial power to get the blades to reverse.
I did not notice any improvement in weather helm with our changing to the feathering prop. As we got better at trimming our sails, most importantly reefing earlier, the weather helm eased significantly.
When we sold Watermelon in Singapore, we agreed to take the new owner out for several days to help him become accustomed with the boat. Because we felt that the feathering prop required more skill than this owner possessed (he was a complete sailing novice when he bought the 'Melon), we put the original fixed prop back on the boat.
Peter and I were both surprised at the faster motoring speed with the fixed prop, and the quicker response when the boat was put into reverse. I had forgotten what we gave up to get that little bit extra sailing speed and reduced vibration.
We had one frightening episode that I think was due to the feathering prop. Rather than relate it here, it's in our log for Papua New Guinea, the 2nd and 3rd paragraphs. http://www.cruiser.co.za/hostmelon17.asp