The reducers and flatteners for the FSQ are 54mm, with a back focus of 56.2 mm. You can get PreciseParts.com to make you a special adapter to the couple the M54 to M42 of the ASI533 that has the precise backfocus. However, their lead time right now is about a month, and you can try to make do with just generic M54 spacers and then an M54 to M42 adapter.
The extender is a different story, since it ends up with a 2" eyepiece holder. You can use a Takahashi CA-35(50.8) (Takahashi part number TKA31201) to get to 54mm and then use the 54mm to 42mm adapter from the above paragraph.
But you can also use any cheap 2" eyepiece to T2 adapter to get to your camera, with some combination of spacers. The back focus needs to be 117.5 mm.
There are various options for M72. One is to go from M72 to 2 inch eyepiece holder (TKP27110). This part should have come with your telescope. You then use the above decribed way to go from 2" eyepiece holder to T2 for your camera.
Another M72 approach, which is preferable, is to use one of Takahashi's "CA35" adapters, particularly the TKA23201 which goes from M72 to M54 (Tak has many different "CA35" for adapting different threads to cameras). You then use the M54 solution I outlined above.
Chen
