Good progress man. The muscle group you're targetting will dictate the type of pull up you're going to be doing. Wide grip chin ups with palms facing away from you are great for back. I love wide grip pull ups. Narrow grip with palms facing you will train bi's/chest more...in the end it depends on what muscle groups you consciously recruit to do the movement.
Just like progress in any other movement, keep overloading and pushing yourself to do more, train with high intensity, and make sure you don't over train. Diet/supplements should be in order. Try getting leaner/lighter as well, this will help your chinups. When I was 180+ I could only do like 10 wide grip pull ups, now at 170-175 I can do 15-20.