I believe SGPro will always show you the actual sensors capture. If it is a 16/9 sensor the image on screen will be 16/9 if it is a square sensor as with the ASI533 then the image shown will be square.
If you want to see what you various focal lengths will capture, most planetarium programs will do that for you, or you can go to astronomy.tools and use on its calculators.
In terms of reviewing the field of view, don’t forget the Mosaic and Framing Wizard. If you set the optics and sensor parameters up, it will overlay the frame over a DSS image. It is easy to overlook this wizard, as some only think of it as a mosaic planner. It works equally well for single pane too.
I’m hoping a revamp of the “flats calibration wizard” could be looked into soon, more and more people use USB adjustable flat panels so it should be a no-brainer to have this as part of the algorithm when calculating the flat time.
It would certainly be a help for people using CMOS with dark flats so they could keep just 1 or 2 sets of dark flats instead of 1 for each filter.
A facility like that already exists in SGPro, though maybe you have something different in mind. I use a home-made adjustable panel and I can set panel levels and exposure times on a per-filter basis, or for “no filter” for OSC cameras, in the profile and that way I can keep a set of flat-darks without having to worry about variations in exposure times. I have an ASI294 camera and I want to make sure that the flat exposures are 3 seconds which meant manually adjusting the panel to hit the required ADU taget, but once I’d done it, I set the values into the profile and each time I run a set of flats, the exposure time and panel brightness are dialled in automatically. Maybe what you had in mind was the ability to fix exposure times and let SGPro adjust the panel brightness to hit a given ADU target, and I admit that could be useful. I also agree that it should be fairly straightforward to search on panel brightness or exposure time and give the user the option of which to fix.