Well, if they were so tight that they would resist the natural centering caused by the rotation of the head, then you'd probably get a real good shake! Not recommended

Do the shake test and you'll be fine. You should have no problem folding the blades back for storage. If it's really hard to do this, or if you have to loosen the bolts to fold them back, you're definately too tight.

Note that many helis shake a bit when spooling up. Once rpms increase, the blades center and the shake should go away. Sounds like that's what's happening to you, so you're probably fine. Do I detect from your post that you are having engine probs? What are you running and how are you setting up the needles?