The Quick fix is easy to keep to body temp. The heating pads can last for up to 5 hours, or you can even put it up against your leg or thigh if you feel uncomfy with it elsewhere. If its up against your skin, its gonna keep your body temp.
As far as the Urine Luck, thats for every day users. You HAVE to be an everyday user. Ive had friends that have smoked on the way to the test then use the Urine Luck within a few hours later and it actually worked. :rasta:
I still say your best bet would be the fix ....most of us here have used it.
As far as delaying the test, i would just go ahead with it. I always thought it looks more suspicious delaying the test. If you do the interview, i think you should take the test.
Hope this helps