Your riding regiment is really talored to your needs I would say. Everyones body reacts a little different to trainning and some need more recovery days and other need less. I would say your looks fine. Your fast group rides should work on ur Anaerobic zone so be prepaired for a very hard ride.
For your heart rate monitor that can be very useful to see how hard you are working. Your heart rate depending on many factors helps you determine if you are working in ur aerobic, anaerobic, or VO2 zones. I normally ride in my anaerobic zones with sprinting and trainning into the V02 zones during rides. It will also help you see if you are working to hard, cause if you are working to hard you could be cause harm. Its mainly their for your trainning to ensure you are getting the most out of every ride and not slacking off.