I just baught a AT900P, 3UG5, 24tension and i put a layer of grip over the manufacturer's grip and what i realize was when i tried to measure the balance of my racket it has loss a little head weight. I was wondering is there any recommended grips or methods to reduce it. Also, does gripping one layer really effect the racket's overall weight or am I just being a little sensitive.
It is very normal. You are adding grip to the racket handle which at the end will increase weight on that part. As a result, racket head part will feel lighter as compared to previous condition before adding grip. Balance point will decrease and vice versa.