Hi
I have only used it with a 16 to 35 mm lens, though it's a pretty heavy one, for 2 min subs but pa wasn't great. The mount is rated for 3kg for visual. Tony Hallas did a review on it and reckoned he could get 5 mins unguided with a 100 mm but it would show some flexure with a bigger lens because of the way the dec is connected and he's right, I have seen that as well but bare in mind he is one of the previous owners of my mount so it could be just this example. His review is here.
http://www.astronomy.com/~/media/Fil...ing-mounts.pdf
Advantage though is it's also good for messing around with the Fs60q.