Since virtually all my wet cure is absorbed by my sliced jerky meat, I would not increase my TenderQuick from more than 2 TBLs/5 lbs of meat. Remember also, smoking is a form of cure used long ago to preserve meat. Some would argue that since we're thoroughly (and I mean thoroughly) smoking thin slices of beef, no cure is needed.
I use the cure as a precaution and as a flavor enhancer. That said, I still store my jerky in a zip lock bag with the air removed inside the refrigerator. It never lasts more than a couple weeks so I can't tell you how long it'll stay safe.