I have an electric tankless that works great, until now. I remodeled the master bath and put in an amazing shower. The problem is I don't have enough flow from WH to take advantage of it. I talked to the manufacturer and was told if I install another WH in parallel I will add the flow of the new. So if my old is say a 4gpm and I add another like it I will have 8gpm. But I don't have a power plant in my backyard only 200amp service. So can I install a gas tankless say about 8gpm in parallel to my electric will I achieve 12GPM. I really need help my wife is irate!!!!