Trevor if the graph was over shooting the guide point your corrections are too aggressive or backlash is comming into play. The best thing about maxim is that most of the following changes can be made on the fly so you adjust in real time and get instant feedback on any changes made. There are 3 main windows you can use to tweak guiding in ver 5.
Window 1: This is the first window you see when you select the guide tab from the camera control window. If you open the options tab click on the "fine aggressiveness" to enable it. This allows you to adjust the correction aggressiveness in 0.1 increments rather then 1.0 which means much finer tunning. You should also set the camera for simple dark calibration under the options tab as it applies darks on the run and there is less noise for the program to sift through. If you then click on the graph tab in the guide window to open the graph, click on the arrow at the bottom and another menu appears. Choose plot --> set telescope axes. The graph plots these rather then the the Dx, Dy of the camera. The X axes is usually RA but you will need to verify this as it depends on which way you have the camera set. I find this really useful as it allows you to diagnose which axes is playing up (eg bad balance, snagged cables etc). You can also set the scale of the graph in this tab (usually use +/- 1 pixel). If you start at the recommended 8.0 (80% correction) and tweak away until your curve is as flat as possible. My mount also has guide rate correction settings ( 0 - 2x sidereal) in the controller which I also use to flatten it some more. I set the RA to 0.6X and dec is left at 1.0X (getting nice round stars).
Window 2: If you select the settings tab from the main guide window you will open the guider settings window. At the top left are the cal time tabs for x and y. I find my guiding is best when I set these so the scope slews at least 30 pixels in the x and y directions during calibration ( I usually aim for about 50 pixels with a time setting of about 15 - 20 secs). Next to these are the backlash settings which I leave at 0 - 0.2 mostly as my mount has very little backlash. You should always have all backlash settings turned off on your mount control as they will interfere with the guiding and set any backlash compensation from here. You can leave all the guider enables x and y boxes ticked unless your mount has shocking backlash in which case you may wish to correct against the drift only. It also pays to have the mount connected through the telescope window as this will supply all the info to maxim and you wont have to use the manual calibration settings and scope dec is automatically read as is pier flip etc so you do not need to recalibrate if you move to a different target. You can also bin the camera 2 x 2 here which makes it more sensitive.
Window 3: If you click the advanced tab in the guider settings window you will be presented with even more options. Under the guiding settings (top left) I usually leave the standard settings with the exception of delay between corrections. I often set this to 1.5 - 2 sec delay but it really depends on the seeing and the exposure time you are using with the guide cam, just adjust to get the best results. I also leave the move command settings alone as well. Under guider motor control uncheck both "y is RA and enable simualtaneous x and y corrections". I dont know about how the EQ6/EQmode responds to simualtaneous corrections but it plays merry hell on the SXD and is not really necessary.
As with all things in maxim you are never just working from one window. I have already mentioned having the mount connected in the telescope window as this supplies necessary info to the guiding function. Another very useful feature I also use is in the camera control window under the autosave tab. Here you have a "delay between" function that will set an interval between the camera downloading an image and the start of the next exposure. This is handy with the QHY camera's running the ascom driver with the "No USB During Download" checked. When the camera is downloading the guiding in maxim is stopped and when it commences again the program can sometimes impose large movements if the guide star has moved too much during the down time depending on the aggressiveness used in the correction settings. I set a 1 - 2 min interval between downloading and starting a new exposure as it gives the mount time to settle and the guiding to get back on track. Of course if you are using a mono camera with filters the autosave window is bliss. You could also use the autosave for a OSC sequence (including darks and flats) and that way it is set and forget allowing you to concentrate on other things (like beer wine and spirits).
Hope that helps
Mark