Don't know anything about shoes and orthotics but how's your pedal stroke? I used to get a numb spot on my toes really fast while pedaling because I was pointing my toe downwards through the entire pedal stroke. Change my pedalling so that when my pedal hit 3 O'clock position, I kept my foot flat and pulled back like I was scraping dirt from the bottom of my feet. It's helped some. Maybe worth having a try along with everything else.