I use them and know a few other members that use them.
From my conversations with Hogg and other fitters its tough. You have to actually put the eSole in the shoe to get the size. My Dad's 44 Sidis use a 45.5 eSole. My size 43.5 Speci use a size 44 eSole. Its weird.
As for arches I would start with normal and go from there. You can always order a bigger size eSole and discard the insole and/or trim it and fit the arches to a smaller size footbed. My fitter did that with both of my shoes actually as I have flat feet and need a size 45 black in both shoes.
That brings up a funny thing there, in the fact that you are flat footed, myself included and you are in the black arches, which are the highest. I had both of the ones in last night I think at the blue, could still feel the right leg wanting to push in at the knee toward the top tube. The black in the left feels too intrusive standing, but not in the right. May try the black on the right/left on the blue combo to see.
I am supposed to be doing some video reviews with Colby Pearce (Trained under Hogg). I wanted to go out to CO, but could not get out there. Who is your fitter?