Hi again Nico I was thinking over the last day or two that if you have a 3 + 1 setup, the knee should probably drop the E strings to Eb rather than drop the D# to C#. I used to have a Sho-Bud Maverick which I think was a couple of evolutions after your Fender but essentially the same pull-release setup. You'll probably get more use from an 'E' lever than a 'D' lever ...
FWIW, if you can drop the Es then you have the following chords at any given position (upper case = major; lower case = minor):
Chord I - no pedals
Chord ii - B and C pedals
Chord iii - E lever (E to Eb on both strings)
Chord IV - A and B pedals
Chord V - E lever and B pedal (actually makes a 7th chord if you play all the strings)
Chord vi - A pedal
Chord VII (or the associated diminished chord) - E lever and B pedal, as per V
Apologies if you know all that already, but I found it really helpful when starting to understand what the various bits did on my guitar
Just realised as I post this that I am assuming you have a 10 string E9 setup - if that's correct then the above may be helpful; if not then it is probably largely irrelevant!