I've encountered similar issues with my ASI1600MM-C and the EFW-7.
1) When Threaded together WITHOUT the supplied "Fiber Spacer/Washer" between the Camera Threads and the EFW, the Rotational Position of the "Tightened" combo is about (but not quite) "square" with the EFW Motor Block "almost" directly ABOVE the normal orientation of the Camera itself. This allows the provided USB2 "Black Right-Angle-B" Cable to plug from the Camera's Hub to the EFW-7 with a bit of slack (the Blue/Grey Straight-B cable provided is TOO SHORT for even this orientation). But it results in the Filterwheel "Sticking UP" and blocking access to Finder Scopes.
2) When Threaded together WITH the supplied "Fiber Spacer/Washer" between the Camera Threads and the EFW, the Rotational Position of the "Tightened" combo is about (but not quite) "square" with the EFW Motor Block about 15* from being directly BELOW the normal orientation of the Camera itself. This allows the provided USB2 "Black Right-Angle-B" Cable to plug from the Camera's Hub to the EFW-7 from ONLY the center-most of the 2x USB2 Ports of the Camera Hub - not quite enough length to reach to the outer-most Port.
One would not wish for Excessively Long USB2 Cables for this purpose. Nor would one want to add to the ASI1600 Camera's Price Point by cost of "Specialty-built Cables". But the current crop of seems to have the above Fitment Challenges.
Don't get me Wrong... I truly appreciate the Inclusion of those 2x USB2 Cables.
