Elle,
I guess my concern is the height and also the position. I always sail from  
the windward side. I hold the tiller in one hand the main sheet in the other.  
This way I maintain absolute control at all times. I am able to stretch my 
legs  for support against the leeward seat. I guess you will  have to work  
through this and figure out what works best for you. I just don't see a center  
positioned seat giving you the absolute control I require.
 
Rummy