I have a Hunter 28.5 and the previous owner removed the hot water heater. I would like to install a new heater but I’m not sure what to look for. I don’t want to have a large heavy heater since we’ll really only use it to wash our hands with. Some exchangers are front exchanger rear exchanger; I assume that’s where the hook ups are. Then there’s vertical orientation and horizontal orientation, I have a lot of room to install this unit so is one better than the other? I was thinking of just going with the inexpensive seaward 6 gal tank. One last question, do I need to install another electric water pump on the hot water side?