Decided to build my own frame. I purchased 2 12' Maxxon tubes. The frame is 80"X40" inside of tube. Frame is 1.25 shed. 40 aluminum. Frame is to be welded. My question is seat location. My plan is to have a front seat on a dry box. Oar seat will be a cooler. The bottom frame extends 17" front and back beyond top frame. What is the best distance from front of top frame for front seat, oar lock location and row seat. Rear row seat. Also plan on a small outboard. I have built power boats, drift boats and thought I would try this. Thanks in advance.