Michael : Hah... Nope, I had a 1kg g-clamp clamped to the front of the dovetail..
It worked, but wasnt perfect as it was heavier on one side than on the other, which when pointed up in the east, would pull the declination axis towards the north a bit... However I think I probably could have pushed the M16 subs out to 5 mins... I really want a narrower Ha filter to blot out the stars and stop blooming all together!