Welcome to the forums .
The eq6 would be absolutely fine for the 4se, it looks like it already has a dovetail bar so you are good to go. 1.3 m is a pretty long focal length for unguided imaging. If you are going to do it you need perfect polar alignment and limit your exposure times. But have a play around and see how long you can go without getting eggs or lines instead of stars, you should get between 1 - 4 mins depending on how well it is set up. One thing that I did for a while is mark a location where I set the scope up, that way I only need to get perfect alignment once, the next night I would just bring it back to the same spot and you are good to go.