The bags that Supra uses are made by Barefoot International, Fligh High. They have the same fittings that the Pro X series bags have. The bags have a quick connect for the ballast system that may or may not only be used by Supra, but the quick connect fittings screw into the bags. What I have done, and it sounds like Diggs has also done, is order the gravity bags; and then use the original rear bags for extra ballast in the boat. If you do that Barefoot international sells the pump and all the fittings so that you can fill these externally.
The factory ballast has one 600lb bag in the front, and the two 450lb bags in the rear. I thought the rear bags were smaller than that, but I'm assuming that is what Diggs is referring to when he says that he has 2 extra 450lb sacks.
When you do the upgrade you buy one 1000lb sack and one 600lb. sack. Put the 1000lb in the front and move the 600lb to one side and put the new 600lb on the other side. The storage inside the boat was designed so that you can run the long 600lb bag through the rear storage and underneath the rear side seat. I'm not sure that's a good explanation, but that's basically how it works. In my opionion, that is too much ballast in the rear of the boat, and it makes the boat dificult to plane if the rear bags are full and you have riders in the rear seats of the boat. We usually fill these rear bags at about half capacity and fill the front completely. Then run the wake plate at about half. I've never had anything other than compliments with this set up, but if you need more (and who doesn't) then you take the two spare 450lb bags and put them in the playpen. The Supra 21V definitely benefits from having more weight in the bow.
This is only an opionion, but it has worked well for me.
In case anyone is intrested, I have pasted my order for the fittings and connectors for my sacks that I place in the play pen or move to the rear for surfing. I already had the pump, so it's not included. The parts can be seen at www.barefootinternational.com .
1 - W733 (11/8" Barbed Tsunami Pump Hose End/Male Quick Connect)
1- W734 (Tsunami Pump Thread/Male Quick Connect)
2- W730 (Female Quick Connect/Sac Valve treads w/ Chain & Male Quick
(Message edited by fhu667 on April 20, 2005)