My optimum drive setting is actually my favorite clean setting, i like punchy strong cleans on the verge of breakup, so when i strum hard it gets gritty. here it is:
90 watt mode, gain trim set onto clean
When I want sparkly, round, full cleans all i do is drop the volume to 12:00 and kick the bass up to 1:00, sounds so sweet it brings tears to my eyes. so buttery.
The problem with this amp is there is not one bad way to EQ. No matter what i do i love how it sounds. It is so simple and so versatile all at the same time. By the way i just found the most amazing ACDC crunch tone. It sounds absolutely incredible. here it is.
45 watts, Blue Mode, EL-34's, gain trim to off or clean
Using this with a Les Paul loaded with a super distortion...No words to describe
However, I am not crazy about the sounds that I achieve out of Lo/Hi gain modes with this setting. I compromise by setting the channel volume from 2 - 3 o'clock, reduce bass, add a bit of treble and/or presence, and adjust my clean trim volume to closely match Lo/Hi gain modes. The clean definitely suffers from this, but I find it necessary to achieve the Lo/Hi gain sounds that I am after while footswitching between the mode.
With all due respect "theweatherman", I strongly disagree that there are "no bad sounds" out of the ED. Honestly, I have to carefully set my ED to obtain "good footswitchable sounds" between all modes for my tastes. However, I clearly prefer "cleaner" clean sounds than you based on your description. Not a problem at all....just my opinion.
I put the gain trim on clean, but heres the thing... I turn the trim all the way up. This means my clean sound is a little louder than the Hi/Lo settings but i rarely play clean a lot, so when i do i like it to be noticeable.
BTW i have 6L6 tubes and run on 45watts