ONE FOOT
I remember when I used to take off on my big bike with a wooden pop box and I couldn't stop until I got back home to the box, or found a curb tall enough that I could mount and dismount from...but that ws long before we had stoplights in our housing communities, and we were allowed to ride on the sidewalks. Smaller profile tires, are the best resource available right now, but like you said to much rake and you either oversteer or severly understeer...it has to be an even drop from front and rear axle to the ground...it's a fine balance, and 1/4" is enough to make things change enough to be felt by the casual rider.