[Farmall] Help with snow plow adjustment

[Ivan Cousins]

  I have a blade off a plow ment for a truck mounted on the farmall A  . 
Works great on my cement driveway , however the neighbors that I plow have 
tar & chip drives . I have the skids down so that I leave about 1/2 " of 
snow on their drives but it still rolls the chips right off their drive way 
unless I'm extra carefull . When it s snowin and blowin after working all 
day I'm not in the mood to take a lot of time .   Which way should the blade 
be angled , forward or backwards so that it doesnt dig in so bad ? Right now 
its almost straight up .  Ivan