Honestly I don’t really go by leaf size.
At this point your plant is not going to make new fan leafs what every it has it’s just going to get bigger. So with that in mind I start and take all the big leafs then I move the bottom under the net and remove close to all (even all the popcorn buds you see) then I go into the plant and remove anything that will make a future problem with a bud site. I don’t follow the 10 or 20% rule. I go in heavy a lot of times I’m 50% or more.
I must also say pruning this heavy comes with risk of plant stress… I personally have not had a problem but it is possible. If you feel the risk is to high do the same thing just take less.
It has taken me many grows to learn how to trim and I’m still learning all the time. The more plants you grow you will see the plant later on and say dam I should have taken that leaf I will know for next time. Alot of the time I trim my plants different in the same grow just to compare what works better. Sometimes I Iose a bit but I win because I gained the knowledge. I know this wasn’t 100% the answer you’re looking for but I hope it helps.