A Level subject combination

Hi all,
I just completed IGCSE exams, and think may get a straight A. Thinking of AS and A2 subjects, with my dream school is LSE, particular: BSc Management, and having 2 questions that need people in LSE sharing experience for my case:
- Double Math: since my school does not offer Further Math, and take exam as private candidate, I am thinking to self taught Further Math, taking Paper 1 (pure Math) and Paper 4 (Probability/Statistics) in AS. Plan NOT taking A2 in Paper 2 (pure Math 2) and Paper 3 (Mechanics). Do you think should do both AS and A2 exams ? People advised me that AS Further Math in Paper 1 and 4 particular are more than enough to economics/management.
- Project combination: I plan to take Economics, Math and Business in my school. I know the Economics and Business having some shared contents and consider as soft combination, especially for LSE, but I don't want to take other subject that creating more workloads, rather get A*A*A in soft combination, better than ending up AAAB or possibly AABB if stretching myself too much. Adding to this soft combination of AS Further Math as a supercurricular. Is it a sound plan ?
Thanks.

a lot of schools don't offer further maths so many unis don't have it down as one of the required subjects. if you're planning on doing three a levels plus your self taught further maths just know that it's going to be a lot of work