OK, I am a solo operator with liscense and all the trimming. I am making a new spary rig for myself. I have about 65 customers at about 5000 sq feet each. I will be installing two 50 gallon tanks on a small trailer. One tank is for non selective and the other will be for selective. Here is where I need your help. I am still undecided about pumps. I have narrowed it down to two choices. One option would be to power with a small 4 hp engine with 4 roller pump. This is a unit set up, so I would need to buy two of these. The other option I though of was an electric set up. I have found a 200 PSI 12 volt pump, about 3 GPM. It might be nice to do some early morning spraying without the engine noise. If I want with the electric set up, I would build a battery box with serveral deep cycle batterys and a hook up to the truck so they will charge while driving. The 12 volt pump was seen on Northern tools. com. Please give me some ideas and advise.