I use TSX for quiding on the hole in my fibre guide head. For the relatively bright stars I am observing I find 1 sec is often the max exposure to avoid saturation, even when the star is centered on the hole.
To avoid chasing the seeing I run the guider with a minimum move of 0.01 arc secs and very low aggressiveness setting (3 or below). This in effect integrates up the individual guide exposures and averages out the move. With the Paramount ME II and Protrack very little guide action is required. The guide graphs looks bad as the star edges the sides of the hole with my poor seeing conditions. The image has a strong stretch.