Thank for the setup advice!

Here is my big concern. The rear diff. I have always run the xray ball diff which was way too easy to adjust. Now, with a gear diff it seems like more of a hassle to switch. I have NO idea what oil to run as our track is small, fast, and technical. I need to power out of the turns quickly and carry power deep into the turn if I want to stay with the leaders.

Traction is so subjective. What I find to be high grip others may say med. How do I tell if I have the rear diff set correctly? Just run the kit oil and be happy?

The carpet is an indoor carper, not an RC carpet.