I would like to build and install a tunnel in my boat. I have been trying to find some dimensions as to what works the best. Some jet tunnels have sides that are vertical from the bottom of the boat to the top of the tunnel and others seem to be angled about 45 degrees. Is there a advantage of that angle? I live in Minnesota and outboard jet and tunnel boats are rare to see. If I could get some pictures and measurements of tunnels that work great I would really appreciate it.