Hi, I previewed the 625 manual once again regarding the support beam.
As far as I can see from the illustrations provided, the support beam supports the weight of the keyboard while it is placed on the wooden stand. Because the board is supported only at its very edges, the tension which concentrates at the middle of the keyboard is possible to break or sag the keyboard after some time. To reduce the tension you need to use the support rail.
However, if you used a double X stand its supports would be close to the middle of the keyboard, therefore there would be less tension at the middle and less (if any) risk of breaking or sagging. The closer the supports to the center, the lesser the risk. The best is when the supports are at 1/4 of the length from each edge.
According to me, you should be able to use a regular heavy duty double X stand.
George
[This message has been edited by George V (edited 06-25-2006).]