As far as payload in the 2S - I have a stock 2S with Corvair - empty weight is 710 lbs. I listed the gross at 1200 lbs. One flight I did - departure weight was @1400 and I was close to the aft CG. I had 6500 feet of runway so I could test this weight. Takeoff was smooth and normal - more sensitive on the elevator but not bad. We climbed out at 750 ft/min at this weight. Again - not bad. Flew 4 hours nonstop to Illinois for the Gathering - smooth flight. I never would have tried this with my KR2 with the VW engine (2180 turbo) but my new 2S performed flawlessly. I dont recomend flying over gross without lots of experience and knowing your airplane's capabilities. I know the rules in the UK are different though and more stingent on some of the aspect.
Bill and 41768 Valdosta GA