Which thickness of rubber would be a good fit for a beginner?

[brokenball]

Does it make a difference? Yes, 2.1 is 5% more than 2. Whether a beginner can tell the difference, I doubt it.
The same goes for 1.9 or even 1.8. I would not try less than 1.8. My chopping paddle has 1.8mm Rakza 7 on the FH. It loops well.

People are adaptable and player skill rules.

 

[TensorBackhand]

In my opinion just start with max thickness and adjust later based on the need.

She probably wouldn't even notice the difference

lol, I think EmRattich quoted this post in his new video:

 

[tabletennisdaily1]

lol, I think EmRattich quoted this post in his new video:

🤣🤣🤣