3 minute shower doesn't sound good. LOL
By running only 2 items at once we would bounce between 5 gpm and 7.5 gpm. If we upgrade to a 75 gallon tank, perhaps we can get 7-10 minute showers.
So I guess my final question is do we stick with 1/2 all the way through, or install a 3/4 valve on the 1/2.
Thanks again for all the info, great website!