Wanted to post a bit of an update to get some feedback. I rebuilt both diffs with new plates and ceramic balls, bedded them in then gave the car a run on wet Tarmac with rubbish tyres to simulate the low grip I had at the race meeting. I found that turning right on power I had understeer and turning left oversteer

so I took the front diff out and replaced the spring and rebuilt it again. This time it seemed much more consistent though by this time it was properly peeing down so I came in. After running the diffs seem looser so I've ordered some new nyloc nuts as I suspect they are coming undone. I need to do a proper run at the track to see if I've cured it but noticed that with the ceramic balls the diffs don't seem to or need to be so tight?
Any hints and tips greatly received