The Speedo Solid Dive suit is an excellent choice for the mature man. It's full cut on the sides with a 5" seam. It's more flexible than the square cut as it is still a speedo. The only bad thing about the Solid Dive is it's only available in black and navy. I don't know why Speedo never offers it's in more colors.
http://www.speedousa.com/solid-dive-suit-style-7300121