This was the biggest grass area I could find on the new Westhill, and I wanted to experiment and try something on grass as a change to all the tarmac routes and autox layouts I'd made previously.
As for the sinking and floating problem, I only noticed after I finished builing my original oval grass track (
LINK) and started driving on it, and although it looks a bit weird, doesn't actually make a difference to the grip levels - seems same as the other parts of the grass track - poor. Even if grip was different, it's the same for all drivers going through the section where it happens, so no-one gains/loses.
Anyway, glad people tried it, and some even found it fun to drive.