Nagell.

IMHO at just over 9Lbs, that rifle in a 450 NE will knock the snot out of you. I don't know what the average is but I believe it to be in excess of 10 lbs minimum. Mine weights 11 1/4 lbs

As to getting the balence point for the various barrel length. I dry fitted the barrels without cutting them for length. Then calculated the weight of an inch of barrel.
They started at 28 inches, I wanted 24". I took a lump of clay and stuck it to end of the stock to duplicate the ammount of weight that I was going to lose. Then put it upside down on a pivot and found the balance point. I had to drill into and add weight to the butt to get the balance right.

Regards