Hi George. I built the entire interior of our KF20+ and mostly copied the whole of the standard design: two bunks up front with mast between, and two in the saloon. I don't remember fitting an infill arrangement to convert the forward berths into a 'double', but that could be doable by fitting battens along the inner edges of the berths with a flat board in between. Then you have to think of a place to keep that board in the daytime... The mast would get in the way some. It's a pretty common arrangement even on bigger boats.