NW2. I wish I could help you predict where you are heading but its unknown. Most people would say you are fine and have nothing to worry about but the future is unknown as I have heard some men going from a NW2 in their 40's and becoming a NW5 or NW6 in their 60's. Its rare but it can happen. However, you are still in good shape for your age so keep that perspective in your mind and you will be fine. All you can do is stay on the big 3 and hope you can slow things down as much as you can. Remember age related hair loss is supposedly different than male pattern baldness. So now you maybe experiencing both at the same time.
DHT blockers don't stop age related hair loss which is also called involutional alopecia. If you can find products that address involutional alopecia, that might help you fight your thinning better. Unfortunately, I don't know of any such products other than Neogenic might address that issue. Switching to dutasteride will still not address involutional alopecia. I think at your age, finasteride is enough to fight against your male pattern baldness if indeed you have that going on as well. Most doctors would say you have a mature hairline and you are not balding yet(NW3). So if you hair is thinning, it maybe more due to involutional alopecia now since you are not a NW3 even in your early 40's. I have seen men older than you with less recession and no involutional alopecia. Those men just hit the hair genetic lottery. Involutional alopecia can start in your 40's and for some lucky ones not until their 60's or 70's. Bill Clinton is a good example of involutional alopecia. He has a full head of hair( no male pattern baldness), yet his density is not as good as it used to be when he was in his late 40's early 50's.