I found these three items which are easy to trim for a perfect fit.
1. Universal gas filler hose HR-9407 Bob Drake Reproductions
2. Amazon Hiwowsport Alloy Aluminum 76mm hose adapter 2 inch
3. Amazon Gates 24712 2inch 45 degree hose. This hose connects to the gas cap.
The front calipers use this bolt: Grade 8 socket head cap screws 3/8-16 X 2. 4 bolts.
The knurled nut is metric -- 11mm.
The rear calipers use this bolt: Grade 8 socket head cap screws 5/16-18 X 1 1/2. 8 bolts.
I am at the same stage with the same questions. Josh at RCR told , me I could cut off the end of the black fuel gauge unit to fit.
Josh also suggested I use closed cell foam to fill the 14 inch space aft of the tank. The foam must be gas resistant.