I dunno. I don't stretch but I do drills that open the hip first, lunges forward and to the side, face the wall squats then rdl's. this always seems to help.
plus, like i said. i don't believe in tight anything. I belive things get weak.
the body gets used to certain positions and starts to like the muscles in those shortened positions...when you move the joint out of it's comfort zone and into an ROM where it's not comfy.... boom. "tightness" the movement goes all wrong and things are not fluid. this is a nuerological problem, not a muscle problem per se. same thing with a screwed up joint, knee, shoulder whatever. you move it to where it iimpinges or abrades or is loos and the muscles reflexivley tighten and then atrophy....this is a lovely cycle that ends athletic carreers and makes life unpleasant.
this is de facto "weakness"....so I don't stretch I try to strengthen the musculature over a greater and greater ROM. so when I'm squattign "wrong" the thing that fixes it is to do it "right"