@ddsmith11111993,
Hi Dan, I agree with you that it's not particular intuitive and it could really do with a user guide or a help option. So far I have not been able to find the original developer of the VGTab utility as I too have some questions.
Form my experience the only things relating to the Fan that may need adjustment is the Maximum Fan Speed, which is the Max RPM the Fan will use in order to maintain the Target GPU Temp, You can also lower the Idle Speed and Target Speed if you want less Fan RPM when the GPU is not being used (for Air cooled cards these two options need to be the same i believe).
I have no idea what the Minimum Fan Sped does as I've never seen my card go below the Idle Speed.
I haven't messed with the Fan Sensitivity, but my guess is that it is used by the PID control to maintain the Target Temp.
I was able to get a bit better performance out of my Liquid Cooled Vega 64 by bumping the HBM Memory Speed to 1045Mhz, some users have manage to get it to run even higher but it seems to be very chip dependant .. some being better than others.
So far the only things I've changed is to set the target temp to 65 Degs C, and bumped the HBM memory speed to 1045Mhz all other values are the default ones for the Liquid Cooled Vega 64, since the liquid cooled model can clock up to 1750Mhz i have bothered messing with the clock speeds.
I know some users have used VGTab to under-volt the GPU and others to over-clock it ... it seems that it's a case of experiment and see what works for you.
The best advice i can give you is to create a config.plist with the stock values for your Vega and save it as config-stock.plist (in /EFI/Clover folder) .. you can then experiment with VGTab settings using your normal/active config.plist until you get the performance and fan control you want ..... if MacOS fails to boot because you got a setting incorrect or the Vega is not happy, you can use the Clover Menu -> Options -> Config to select the config-stock.plist so you can boot with the stock settings and fix the problems.
As a start i would just use VGTab with the stock settings for your Vega and see if helps to calm the Fan down and get the temps under control. Then if you feel the need play around with some custom settings use the method above.
Cheers
Jay