I'm trying to come up with a budget and would like to know what type of wall to build. I have attached a photo showing 4 different methods, what style of wall would be the best. I know # 3 would be the strongest but is it really necessary. I have seen walls built like all shown. Also would 2x2 be strong enough or should we go with 2x3 or 2x4? If you have any other ideas please share.