Theoretically speaking? How does the L1 switch work? Is it "intelligent", or does it simply select between two power levels which are in the head of the light?
I believe that the tail sends a signal--as in it's only one half of the brain. The other is in the head of the L1, so putting the L1 onto the L4 shouldn't give you the result you wanted.
The L1 head is dumb, the magic is partially inside the tailcap and body. First of all the L1 switch won't fit onto the E-series lights and second it won't work.