Thank you Squirrel! Here's a recent pic, just for you :)
JThiessen, finding the perfect diff oils is always a trade off. In RC it pretty much all depends on the amount of grip your area/track offers. Basically, I want them as stiff as possible, without spinning out under hard acceleration, but not to light as it would unwind on the wheel with less traction. See? Hard to explain for me.
For example in the center, too stiff would even give you wheelies, and too soft would only result in balooning front wheels with no acceleration.
Front-to-rear ratio depends on driving style: DO you want the most traction in turns, or do you like to drift through them, or do you only want to swing its rear, etc...
Hope this helps. Playing with 8th scale buggies gives you a good feel for it.