Use as much as possible. I use twin 850lb sacks... one on the side of the doghouse and one behind the doghouse. Wish I had another 500-1000lbs back there and 500lbs in the front.
Also, unless you add weight or bodies to the front, make sure to adjust the trim plate down. This pushes the nose down and will help stretch the wave out. The Saltare has more push than any other wave I've riden (it should.... with all that displacement...) but it can suffer from being really steep and fairly short. Weight in the front or adjusting the trim plate will help this.
Former owner of a 1987 Supra Saltare. Current owner of a Malibu 23LSV.