I could give you an exact lesson count, but it doesn't matter - each lesson also has varying depth. I would roughly say that i spend an hour on one lesson - some shorter, some longer.
I can say that Module 1 is roughly 35% of the meat, Module 2 about 40 %, and Module 3 seems fairly short .
BGS has their revision courses online (and in person) on a weekly rotation. This was the biggest selling point - i couldn't bare the thought of having to wait months for the next, or having to travel somewhere to finish the course.
If you got 4 hours a day to spend, every day, you can absolutely do this course in 3 months if you dont take breaks to study other question banks or do the exams. I wouldn't recommend doing the exams with only Bristol. I've learned a lot of stuff at AviationExam that Bristol didn't cover (or maybe i snoozed over those parts).