I have always had very tight hamstrings, tried everything but can only stretch them sofar.

my problem is during squats which i do with a wider than shoulder stance, my lower back tends to round at the bottom of each rep. the bottom for me is just past paralell. should i only goto paralel even though it is less effective and i find harder than bottoming out.

i have also been diagnosed with a back defect at birth, which means i am missing an attachment or something in the very bottom vertabrae.

SHOULD I INVEST IN A $500 U.S CAMBERED SQUAT BAR.???
it is cambered 4 " and has two bars[a yoke] perpendicular to the bar which rest on your shoulders.
in effect it lets you squat in a more uprite position similar to front squats only it is not painful on wrists and shoulders like front squats

HAS ANYONE WITH BACK PROBLEMS USED THIS BAR OR ANY OTHER TECHNIQUE/EQUIPMENT TO OVER COME THEIR BACK PROBLEM