Simon - Block to Block works well on a Hobie 16 in the proper conditions . Obviously - if the above quote is correct - you should not do it on you boat. I don't know the Spitfire, but as Wyatt said (Hi Wyatt), you rarely (I thought never) do it on a H-18, for example. So block to block is not a standard. Try sailing a Stiletto block to block - you can't.