It depends on the image scale, of course. My 30 minute subs were at about 3 arcsec/pixel, with the amplitude for that setup (a SW120 with an ASI120MM on an OAG) being consistently <1 arcsec/px.
I haven't tried that long (yet) with my C8 which will give me about 1/px image scale, but that's only because I only relatively recently got the OAG - not for any fear that it might not work. I've heard that if you mesh the worm too tightly, it can cause real problems. The slight 'slop' is there for a reason, and if the play is not too large and not causing guiding problems, I would not worry
