I am trying to connect my fatsacs to my factory ballast on an 07 malibu 23 lsv. Has anyone done this?

Try the malibu crew lots of people have done it.

Take black hoses closest to the seats on the thru hull and plumb into the bottom of sacs using brass/barbed fittings. Then get 4ft(8ft total) of clear 3/4" or 1" hose and connect to top of sac w/ brass/barbed fitting and out the original thru hull. This will fill and empty with stock switches. The sacs are done when 2 streams of water are coming out the back. This will work for the rears but I have seen a few people have a quick connect for a front sac.

just ask DR. J to do it

The Piggy back kit has everything you need