Moomba Outback center/front ballast

I became the proud owner of an 08 Moomba Outback DD about 2 weeks ago. (see "which boat for 30k thread") Allready the mod bug has bitten. I replaced the stock 350lb bag with a 750. makes pretty good diference. Now im interested in an under floor or under bow cushion ballast upgrade. the area is small, so 300 lbs would prob be all Id get. There is a small hatch in the floor richt in front of the motor that goes all the way under the front bow for access, and of course I can just pop up the bow cussions to fit something under there. So what is the best thing to do to get a little weight forward, but not just be a sack in the midde if the walkway? Custom fly high sacs? I want to plumb it into the stock system. perhaps with a valve so I could turn off/on the bow portion. Ideas? What have others done? This boat is small for wake boat standards, but huge for me. I came from a closed bow 18 foot. Either way it goes, it has to be vented so I dont break fiberglass!