Bob,
You may not have allowed enough room for feet/pedals with the centre tunnel the way you have it now. I fabricated a similar centre tunnel but with less height/elevation(but sufficient for two 50mm coolant pipes) but where I joined the front bulkhead the profile went from being rectangular about 18 inches from the bulkhead to Triangular biased toward the passenger foot well. If this isn't clear I'll get a photo of it this week. I didn't use the pipe covers in the passenger footwell as my coolant pipes are , obviously, down the centre. so there was room to put in a passenger footrest like the rally cars use.
I didn't put a handbrake in the centre position either - I think that as I have seperate hydraulics front and rear, an hydraulic lock lever will work as a parking break in addition to leaving it in gear. Sure - some will chirp up that it cannot be permitted for our Ministry of Transport tests but thats taken care of as well.
Unless you have tiny pieds, try your foot well positions and see how much space you have.
I'm assuming this is a GTD?
Dave M