You have to leave the print for a standard amount of time in the fix, or your print will not be permanent.

Ilford MGWT is tricky if you want to pull the print by inspection. But it can be learned. The paper is very consistent with how it looks by the time you need to pull it. There are no shortcuts. You need to learn what to look for, because you need to completely fix your prints.

Practice makes perfect. I know Ilford MGWT can be very expensive paper, but how else will you learn? You need to develop a skill where you can trust what you see. Get good safelights! I recommend a couple of amber ones, and they will help you identify when your prints are done developing.