How many springs do you use? Is one of your Strats dedicated to Eb tuning only? Did you switch string gauge or brands when going from E to Eb tuning? Mine is a 92 MIM Strat with a mix of Fender noiseless bridge, Fender USA alnico middle and a Duncan Antiquity II neck. D'Adarrio 10 set still (as I always use), 4 springs and the action a bit higher. It feels and sounds really good right now.....BUT, as always being the tinkerer I am, should I go to an 11 set of strings to get an even bigger sound ala SRV (though SRV used 12 and 13 sets I guess). Any other observations or info is greatly appreciated on a Strat tuned to Eb!