Hi Mike -

Take a look at our approach. Several of the pictures are annotated. We used aluminum bar stock also and located the seats 3 inches further aft than recommended. Both of us (6'3") are comfortable now. The rail extensions are hysoled into two slots cored out of the prepreg cover. WE split this cover so that we can remove the whole assembly for a seat at one time. We put the extensions in a cored out area because head room is also anticipated to be a problem and that 1/4" can make a difference.

Cheers,

JOhn