Alex,
I am using exactly the same electronics and motor on my EQ3-style mount for wides (well... I used to use it in the past).
See here:
http://www.iceinspace.com.au/forum/s...ad.php?t=45079
The main problem was PE, introduced by worm gear.
It is OK for ~100mm, above that exposure time must be reduced to cope with PE (up to 30sec or less).
Your worm gear (from wixen mount? or is this LXD 50?) is presumably better than mine (from who-knows-what-manufacturer)..