What diff oils Losi 8T Brushless

[gramey]

I've bought a new Losi 8T RR which I'm converting to brushless with a Teknorc V.3 kit, Neu 1515-1Y motor using an MGM 16018-3 esc and Flightpower 4S 25C 5000mah lipo's. my question is what would be the best combination of diff oils for this set up, hard packed loose topped track?

I run 5/7/3 in my nitro 8T but I think most people are going a lot higher with the B/L especially in the centre diff