Do you mean Kreitler? As far as set-up the length should be adjusted to match the wheelbase of the bike. You need to use a plumb bob from the front axle or something similar. Go to the Kreitler website for the specs.

That will make it stable, or at least possible to be stable if you are doing your part right.

The main thing about riding rollers is to not pay attention to all the "scary" stories about riding rollers, because I do not think any of them are true. You just put a milk crate next to them, step on and start pedaling. Stay loose, and light on the bars. Look forward not down. Spin and let the boredom set in..............