hi all... i've recently started expanding my business to include more service work,,, specifically drain cleaning. i just walked through a three story, 30 unit building with the property manager and he wants me to price out cleaning all the kitchen lines. great opportunity to get in good with a management company, but i fear i'm in over my head,,, i'm new to drains (have done a bunch recently, but limited to showers, lavs, the odd water closet). anyways, where to start? do you guys with experience simply pop off clean outs in the parkade and snake the horizontal portions, or do you continue up?? what about getting into the third floor unit and cleaning down? any help would be great! thanks,