[gumby79]

5.2.12 No streamlining may be attached to the rider.

..... this makes my prvious tail/butt fairing useable, unless it is attached to the tail of the bike.

5.2.12.A. All fairings must be made of plastic, fiberglass or carbon fiber.

.... Theas are the materials you can use for your mods. Except parts associated with drake cooling and wind deflectors.

5.2.11 Fairings must be mounted in at least three locations. The front wheel
must be clearly visible from both sides except for the portion covered by the fender. The rider must be visible from the side and above, while in a normal riding position, and transparent material may not be used to allow for such visibility.

....I read this to mean the entire front wheel/tire can be covered by a 1pice finnder

5.2.4.C. Aftermarket brake cooling ducts or wind deflectors may be made of metal providing the design does not pose a safety risk to any competitor.
Final approval of unit rests with the Tech Inspector. (each and evry race)

A 1 pice finnder would combine both 5.2.11 and 5.2.4.c

5.2.10 Rear fender or seat must extend to the rear of a line drawn vertically at
the rear axle.

They state a minimum... no maximum. Added length is a compromise between reduced aerodynamic drag and increased Rolling Resistance coefficients. Use Aerodynamic & rolling resistance, power & MPG calculator - EcoModder.com to figure out how far you can go and see a benefit.
Gumby Stay Flexible.