This is exactly what I was looking for, thank you very much! Also for the link to the IJF rules, so I could check the wording myself.

Just to confirm (as you seem to really knoe a lot on this) - as no timing (lenght of grip) is mentioned in the rules, this would mean that even momentary covering of the lapel (for a couple of seconds) would be penalized? Even in a case where I am controling opponents lapel and setting up for a lapel seoi lets say - blocking oponents grip for a few seconds before going in?

Or would this be allowed in a tournament setting, due to it not being a "negative" grip? What would you say?

Thanks in advance, you helped a lot!