I dont sail formula gear but lightweight no... got down to 83 last year now probably about 85-90kg. Before that have been as heavy as 110kg. For my sailing style/rig size I use 90kg is about perfect (enough weight to hold rigs down but dosent affect early planing). Was looking through an old magazine the other day and the weights of the pro's

, heaps above 90kg or more significantly all the top guys above 90kg.
Cool article, didnt know not to twist body forward. Aerotech make formula sizes down to 9.0m if you can wait for this year's model due in march (Patrice has been working on this one so should be good for formula).