Looking for advice on laying out 6 balls - I have the lower end pretty much covered with my current arsenal, because thats all I need for our THS. So I'm looking to fill the medium-light to heavy range here.

Some info about me -
PAP 5 1/8 x 1 up, 275-290 rpms, 15-16mph avg., average 210-215.

Here are the balls I have now ready to drill, I'd also appreciate suggestions if you feel there's a gap anywhere. (tax returns coming soon)

Lanemasters Guaranteed 3" pin
900 Global Bounty Hunter Pearl 3 1/2" pin
Hammer Black Widow Pearl 3" pin
Roto Grip Cell 2 1/2" pin
Roto Grip Cell 2 1/2" pin
Roto Grip Horizon 5" pin

Again, looking for mostly layout advice, or advice on new equipment. Thanks!

-Andy