the blade grip tension should really not have much effect on their tracking unless theyre out of balance. If they are not balanced CG wise.. (center of gravity) its best to keep them a little tighter than normal. The better the balance the blades.. the looser in the grips you may maintain them, which adds to fluidity and effienciey, Most new pilots tend to keep them tight as possible but able to "give" at impact for obvious reasons. whichever method you use to test their tightness, its best to take in consideration also are they too loose and floppy? Tolerance is critical when it comes to helicopters.. and it rides right there with balance, and the amount of tolerance you wish to maintain. the tighter the tolerance, the tighter the turn.. or.. impending disaster?