"thomasair"Zebra,
For me, the vast majority of my sitting shots are taken with my knee riser in the very same position. So you could easily just make a static riser and probably be all set for most of your sitting shots, too. For my kneeling shots, I like a different position. For offhand, i typically don't use the riser at all. However, there are times when targets are placed in trees that require an uphill hold of maybe 30-40 degrees. The offhands and kneelers can be very difficult to find a steady hold if you don't have a good range of adjustment on
the riser.
I would suggest just making some simple static risers that connect to your Anschutz rail and shoot for a while to see what your particular needs are. Here in the US, we can change accessories on the lanes in the open class. Wftf does not allow adding or removing during the match. Lots of open class guys have static risers of various height that they freely change out as necessary. That would be the least expensive route to take.
I read somewhere that a guy used toilet flange bolts to hold accessories on his Anschutz rail. I don't know if they required any additional modifications to utilize, as I have not tried them myself.
You can buy Anschutz rail sections from Champions Choice for about 15.00 for a 15" piece. I don't have a direct link, but if you go to their site and search rail sections....it should come up.
Mike