Everyone is going to be different. When I work with an athlete on a contest prep, I always give them at least 16 wks, even if they are lean to start. This way, we can get in shape, ideally a little early and coast in. For leaner guys, we usually can add some muscle in the dieting process. If someone has more body fat, it is going to take longer to get lean. Everyone responds differently to a diet. Some guys lose fat quickly, while others have to suffer, even on keto. My suggestion would be to get yourself to no higher than 14% before you start your gear. Then I would run it for 12-16 wks. If you can't get lean in that period, something was wrong with the plan to begin with.