What is an acceptable driveline clonk?

My GRiSO 1100 4v 2007 seems to have a lot of rotational slop in the driveline when back wheel is off the ground and Le Clonk when letting clutch out or feathering is annoying. Is there an acceptable measurement tolerance of slop? Looked through workshop manual and through these archives but couldn’t find a measurement. I guess the play could be measured as a rotational direction angle with the wheel off (where did I leave my old timing disc) but I dont know what to compare it to.
Just had a thought - my iphone LEVEL app might be useful perched on a wheel spoke.
Any thoughts on acceptable/excessive lash appreciated

The backlash in that situation is quite normal. It's the backlash between the dogs of the selector system.

The 'Clonk' will be a mixture of the reaction rod bushings and, on an 1100, the face cam shock absorber on the gearbox input shaft. Dealing with the rod bushing is easy. The shock absorber? Bit harder.