We are set to dig next week - woohoo! We had agreed on depths 3.5 (entry) , 5 (middle), 3.5 (far end). Someone had suggested doing 3.5, 5, 4 as it would be more comfortable for adults in 4ft of water. We have younger kids (but I know they won't be little forever) and we would like this to be a sports pool. Any advice?