Unless you're a really big guy and need a really high gear capacity, you might want to rethink the 25" beam. That's rather excessive and it will result in a slow boat. While the stability of a wide beam is comforting, most paddlers "outgrow" wide boats pretty quickly and end up going with something narrower. There's a reason that 17' x 22" boats have become somewhat of a standard in the industry. It's a "sweet spot" that provides the best balance of stability, capacity and performance for most paddlers. If your needs differ from the average, then definitely adjust your design accordingly, but I would suggest going longer if you need more capacity, rather than wider, as you'll end up with a better performing boat that you will likely be happier with in the long term.