I told you man, I really don’t think most beginners will be able to grasp this yet. I totally agree with you on what you wrote about light weights(I use the 30s-40s for curls myself nowadays but I can probably use the 60s if I need to impress some Emma Stone lookalike in yoga pants) but I’m very sure most of them will just going to be going through the motions and using very high reps to be able to get sufficient stimulation and a pump.
On the other hand, I really want to see if it’s possible to teach this to them at this stage. It will save a lot of joints in the long run.
Do you know how to REALLY FLEX your biceps?
^Try the flex behind the head thing. Remember that feeling. When you do a curl, do not think about moving the weight. Think about flexing the bicep. You will probably only be able to lift half of what you are using if you do it right.