The “L” size has no flex to speak of.
Well... The Dive Rite XT fins feel quite a bit stiffer, to me. I guess that might be because they are longer, but the "feel" is that the Deep6 has more flex anyway.
My preference on the Deep6 is definitely NOT that they have any MORE flex, that is for sure.
I just want some that are identical, but more negative, so I can ditch my Hollis fins (which are great, but I like the feel of the Deep6 better).