I would recommend only worrying about 'RAW16 (Ultra Low Noise)'. That mode does get read noise a bit lower than the normal RAW16, so is worth using. RAW8 is not really of interest for deep sky - useful for planetary/lunar/solar, but no need for sensor analysis data for that.
The 'High Full Well' mode is (in my opinion) a bit of a pointless feature for most people. You can get very high FWD values, but at the expense of much higher than usual read noise, which then pushes you to longer exposures. It might make sense for heavily light polluted scenarios where you are fighting against the quick build up of the light pollution background, but otherwise it is more of a 'tick the box' feature - when one brand adds it, all the others need to do the same to avoid losing out when someone draws up an excel spreadsheet comparing which brands to buy...
In general, I'd say try starting out at 300 gain, which is where the IMX571 cameras made by ToupTek/Altair switch into HCG mode in SharpCap. You should enjoy using it - the IMX571 sensors are great with very little pattern or thermal noise.