My business mostly does maintenance, fert and aerations. I want to get my licence so I can truly be full service. I would like to start small for weed control and avoid buying a tank if at all possible. Even if it means a little more work for me. If I am doing 5 lawns a day, spot treating with a post emerg like Killex once a yr for a total of 50 customers can I get away with a backback with a good high vel nozzle?? ty very much for the help on this. I really want to get my licence but am still new and am paying off equipment. P.S. my supplier has Killex but where I used to work we used Par3. Is Killex as good?