Celestron Nexguide with Celestron Off Axis Guider

[thelargemonk]

I'm after a bit of advice as I have been having issues with the Celestron Nexguide. I have a CGEM DX with 9.25 OTA and have been taking some images unguided, but want to start doing longer exposures.

Last night I tried  to use the Celestron Nexguide with the Celestron Off Axis guider to try to stop the star trails and do some 2 min exposures to start. 

I had the mount polar aligned spot on and it was hitting everything bang in the centre that I told it to go to and keeping it there tracking wise.

My issue then came when I tried to lock the Nexguide to a guide star. I tried several exposure lengths on it from 200 to 1000 and different noise reductions on all of the exposure times trying not to go below 10.

At shorter exposures of 300 to 500 It would lock onto a star, but would be flicking all over the screen as there were several other dots on it, but if noise reduciton was then put up it would lose the star all together. So then at 1000 per sec it would create a small black solid block at the very top of the screen and a long elongated box. When I set it to lock onto a star with shorter exposures it then went back to what i think it was doing flicking to different stars each image. 

It would then be making big adjustments to the Dec and Alz and ended up with some pretty big star movements jittering all over the place which I tried to attach, but are to big.

Does anyone have any tips or is it not the best using it with an off axis guider on a SCT at F10?