I think copying (and resizing) existing scale models will be your best bet, then crosscheck those new dimensions with the regulations. For example, the RW endplates will be good to crosscheck, as will the tires, front wing width, car width, etc as they are a constant size.
Measure twice, cut once. Good luck!
I've found a way of ducting exhaust right to the diffuser edge like in 2011 and created a new wheel fastener that could allow sub 2 second pitstops see them here --> My 2013 F1 Concept Project