Hi mate,
i also used 100% R/D.
in regards to diff oils your not far off. Its all about personal preference but i ran 20k in front and 7k in the rear. This calmed the car down greatly and stopped the front end biting in on long sweeping corners.
Indoors in would take all the weights off your car, i did this for the last round of qualifying and put in my quickest time of the day (just missing out on the A final by a few seconds, if only i didnt crash on the second to last lap!
).
At the Petit i also cut 1 row off the front tyres just to make the steering little smoother and again to stop the front from snatching. This is not the norm though so i would leave your tyres without any rows cut off and see ghow it goes. If its too snatchy then maybe consider cutting a row off the front.
Craig Collinson