I am assuming this is a Sunsetter LX cause you said 21' but if its an LXi I can help you make the best surf wake for that hull (cause it can be tuff.)
For surfing you really need to get all the weight to one side, but more importantly IMO, you need to get a significant amount of weight in the bow. On my friends 03 VLX (same hull as the now v/i ride and your boat) we put the wedge down, a 500lb sack in the bow port side, center MLS full (throw a sack in the ski locker), 500lbs in the back port locker, and another 500lbs. on the seats port side. This really throws a great wake I think. The 500lbs. in the bow helps to lengthen the sweet spot as well so you have room to play. I hope this helps, and if you have any more questions (not to steal you away from this site, but) come and visit
www.themalibucrew.com and you will get more info on your specific boat then you will ever need.