We race a rear-engined modified roadster at 3400#,currently 60% rear, 40% front with fuel and driver. The first thing we do at the Salt is put the car on the scales with the driver and check corner weights and ride heights (compare to set up in shop) after the 2200 miles "shakeout" trip from NCarolina. This also allows us to zero the shock pots for the data system. Some people look at us like we're nuts, but we've been doing racecars - road racing and oval track - this way for so long that I'd feel like I cheated the checklist if we didn't do it on the Salt. I have heard that shorter wheelbase cars like you mention want closer to 50/50, but you need to balance adding downforce and drag vs grip at the rear wheels. Trevor Harris once told me to exhaust all avenues of balancing a car mechanically first, then apply aerodynamic aids once you were out of mechanical solutions. I've followed this for the last 20+ years. I would start out at 55rear/45 front and rebalance as handling dictated; I hope that others here with more experience with your class vehicle will provide more proven solutions. vic