In most instances in a lake where feeding and management have occurred and then that is stopped you will get an overcrowded LMB population quickly. That is what you described in saying low RW and skinny with a large head/shoulders. Goals are key but to make any progress you need population analysis and water quality info. I suggest you call Bob Lusk at the Pond Boss office as he has worked with hundreds of lakes like yours.

Best advice - that is way too much water to manage by yourself. You will need help. Just harvesting enough LMB to maintain balance will be a more than full time job and you don't want LMB harvest to be only by fishing.