I could typically average 40% of windspeed up to around 20 knots of wind, in cruising mode. Lightship I can get up to around 10 to 12 in 20 knots of wind on my FP Tobago 35, cruising in the relaively protected waters of the Baltic, but with short choppy waves. This was with the standard rig.
I have now got a rotating wing mast(33 cm chord) and a large flat top main that is 1.5 meters taller. During the last week of cruising we have been able to average around 7.5 knots in 12 to 16 knot winds, mostly forward of the beam.
Had a lovely sail this morning between some islands where we averaged around 8.5 knot in 12-14 knots TWS. We are fully loaded with 4 adults, all their stuff plus dinghy, outboard etc, so I'm really pleased with the new rig and sails
So adding around 45% to the mainsail area, rotating mast, new main and self-tacking jib have improved performance from 40-50% of windspeed to 60-65% at 15-20 knots of wind. The improvement is even more at low wind speeds of say 5-6 knots, now I can actually sail!
Regards
Alan