It could be that you are going about this the wrong way (or the wrong order).
Like whammel says, best to see a decent physio. It was a physio at my local MS Therapy centre who first measured the length of my legs. It was an orthotist who then measured them very precisely, and after saying that the right leg was 10mm shorter than the left, produced a wedge as a temporary measure. So I now have a pair of half insoles that take care of my flat feet, one being thicker to counteract the shorter leg, and the other having the heel switch for the FES embedded in it (means it is always in the right place. Now I can think about shoes.
Just to complicate things, my right foot is half a size smaller than the left. So, I have to get shoes that will take the orthotic insole - think wide fitting - and worry about the right foot later.
So, get the drop foot sorted (FES if possible, but SAFO if it is not too bad) and then start thinking shoes. The FES means wires and electrodes on your leg, and that means trousers most of the time, and that starts to dictate the choice of footware. If you need anything wider than EE, that means a specialist shoe firm (most of whom do mail order and home trial). A good shoe shop (if you can find one) will measure your feet, help you with putting the shoes on, and then let you walk round in each pair.
Properly set up, the FES should turn your toe out before lifting it up (I quote the experts at Odstock) but if this is not happening (or not enough) you need to get it sorted (or do it yourself by moving the electrodes in very small steps, and testing). If you still have a problem after this, get your leg length checked - accurately. Then you can start thinking about shoes.