You have to double the amount of rind when using a Meyer lemon in recipe. Same with the juice. We made a lemon Mer-ange pie and used 2 tablespoons zest and 1 cup of juice. It tasted 2 time more lemony with no additional tart and was twice as nutritious because it had 2X real lemon in it.

Sounds yummy!

My question is not how much rind I have to use from a Meyer lemon but which lemon cultivar has the most intense.

The best "lemon" if you want to use the peel is actually not a "lemon" but a citron.

Citron is the main ancestor citrus species to lemon.

The peel of a citron is less bitter, and more tender than the peel of a lemon.

Okay, so which citron would you propose? I only tasted Buddha's Hand but didn't like it's rind so much.

As I understand, Buddha's Hand is a true citron,(Citrus medica). I don't think you will find Citrus medica 'Etrog' to ba any different.

I haven't done a lot of zest tasting across other varieties but I am always impressed with the intense lemony aromas from the Ponderosa. It really doesn't fit your non-bitter requirement though. I think some do consider it a citron. It is bitter by itself but does work very good where zest is called for.