Interesting to note that Patrick Head said that the last Williams designed by Willis didnt feature a twin keel which he thought may have been overlooked and now the have possibly the most dramatic version of it whilst Newey continues to advance his designs....
Now Sauber who started the trend have gone back to a single keel, which as stated elsewhere is prob based on their extensive use of the F2003-GA as a basis of their design...
how many designs are using it now?? Mclaren, Williams are but not sure bout the lower teams...