Muscle adaptation

How long would it take to make a person fast twitch muscle fibre dominant over slow twitch, and vica versa? For example, if I am in the weight room doing 10 sets of 130 reps, how long until my fast twich muscles have wither changed or atrophied? 1 month, 3 years?? And…vica versa.

I’m sure it would differ a lot between individuals, but I too would be interested on hearing anyones experiences with this.
I find this idea very interesting, and also wonder how you would measure such adaptive changes? ie. times, strength levels, general explosiveness, etc.
Another question related to this topic: How far can these adaptive changes go with long term training? (5-15 years, etc.)