We use Port Hard Tank on our 2005 X2 and front locker tank. In addition we put 350lb sac in the V-Drive on Port side. 350 port seat all the way back. 3 - 85lb sacs on port seat, 3 - 85lb sacs on port side of bow. I sit on the port side locker (160lbs) 40lb daughter sits in the bow (her choice not mine) and wife drives (She is 5'6" and wears size 8 - that should keep me out of trouble putting it that way
!!!!) The best ride for us is between 10 and 11 mph.
Good Luck!!