Hello Macca,
In the 1980s when SC20TRs were sailed by top caliber sailors, this boat was rated in the PN range of 62 to 60 when the Tornado was 64. This is US Sailing talking, not me. So there has already been a 20ft long production boat built that is faster than the Tornado.
My son and I took one of these old boats, an over weight one by 100 pounds, and put some new sails on it and won the 2003 Steeplechase race, 100 miles long, by 25 minutes over the second place boat and that included a turnover and righting on our part. There were Tornados and I20s in the race sailed by the top caliber sailors. At the time I designed the SC20,1976, I had never designed a boat before. I had 20 years sailing experience in monohulls. I had engineering degrees and all I knew were "those ratios". Those ratios worked back them and they still work today. If your effort to put together a boat faster than the Tornado is to succeed, you better check those ratios and see that your system exceeds the Tornado in "those ratios".
The M20 is definately tailored to the windward leeward race course and suffers on the close reach. Adding a small jib is very easy task. The Eagle 20 platform and rig may need no development at all. If the boat is designed and built by knowledgable and experienced people, they can hit the nail on the head first shot out of the box. I am willing to assume that this is the case until I hear otherwise. Winning the Texel race against the M20 and Tornado even by 1% says to me that the boat is at least equal to the best 20ft designs right now. I'm sure the Eagle 20 has some excellent "ratios".
Bill