Hey, I wish you guys would just chill for a couple friggin days on the ballast thing. I pretty much finished my souped-up ballast calculator spreadsheet this weekend. Got instructions finished today, so probably tomorrow I email it to Mr. Cyclone for posting. It's pimp, that's all I can say.
Might not exactly help with this thread's questions, but it'll keep you busy for a while.
For starters, you need to put the 1000-pound Fluid Concepts bag in the trunk. Get over that. Put your back seats back in and enjoy their cushiness.
For the bow, either you place a Big Bump in the walkway like I do (you'd have a pretty clean 1700 pounds), or you get a slightly smaller deicated bow sac like Launch Pad's 440-pounder and then have a custom triangle sac made to take the place of the bow cushions and lay over the walkway sac. I'm thinking like 8" deep so you can still use it as an open bow. That'll add around 420 pounds. The only loose end there would be how to handle the open spaces in the bow where the cushions used to sit - you could either cut a nice sheet of like 1/2" nylon -OR- you go ahead and fill the three compartments with a special U-shaped sac. Not only might it add a couple hundred pounds, it'd support the triangle sac above it.
Call that setup an evenly-distributed 2K.
Final option would be to replace the rear cushions with a bag similar to the Fly High Rear Seat Bottom Sac. It's 26" deep, 62" wide and 12" deep. I'm not sure what it looks like under them cusions, but assuming it's like floor there, this pad or a custom one like it could be made to occupy the same space as the cushions it replaces. The Fly High I metioned is rated at 680 pounds, but I'd say to just replace the seat - don't go higher or deeper. This'll give you back the space you lost to the Sofa, and still add several hundred.
If you were willing to just get nasty, there's a triangle bow sac ready to go that's rated at 1K. Have a custom sac for under it in the walkway, and the u-shaped one, and you'd be pushing 1500 in the bow. Add a Sofa to the FC 1K pounder in the trunk and you'd be right at 4000. Now that'd be a manly wake. Might want to turn something like a 13x10 prop, but it'd do it.
The main bummer with the Bump in the walkway is that you lose access to the cubby: "does anybody need anything out of here?" Then you seal it up for the day with 700 pounds of water. with a Fat Buddy or other short sac in the walkway, you can keep the cubby useable. Add the u-shaped sac to that and then lay over the custom cushion-thick (6 to 8") triangle sac, and you've got a nice 800 or so pounds with a perfectly useable bow seating area and cubby. I'm sure there'd be an easy way to speed filling and draining the three layered bow sacs, and the one in the trunk would be super easy. A custom rear bench seat replacement would be super easy and could be done pretty cleanly so as not to take up any more space than the stock rear seat.
Better buy in to a sac mfr. and decide how many RPMs you're willing to cruise at around 22 mph. 4,000 might be a good start.