Edmullinsphotography I have it inserted all the way into the helical focuser and have the focuser adjusted to get the camera as close to the prism as I can
From your desciption, you need perhaps just a millimeter or two of shorter optical path between the objective and the guide sensor? You did not mention how much the focuser needs to be rack to bring the guide sensor into focus.
Assuming that you only need a millimeter or two, pull the prism stem away from the optical axis to achive a shorter optical path (i.e., from triangular inequality, the hypotenuse of a right angled triangle is always shorter than the sum of the other two sides).
By doing this, you will get a smaller prism shadow on your main camera (good), but the guide camera will be working further out on the imaging circle of the OTA (bad). So there is a compromise. To avoid guiding on stars that look like tadpoles, don't overdo this. Pull the stem only as much as needed, and no more.
Chen
