Definitely not both. Both finasteride and Dutasteride severely drop the conversion of testosterone into DHT. Duta is somewhat better, cutting it on it's own at a 0.5mg daily dose down by around 97% after taking it for an extended period of time. Taking more than that dose, or doubling up on drugs that do the same thing is completely unnecessary.
I am a 28YO diffuse thinner. I started taking duta around 4 months ago, after continually losing hair on minoxidil. It's too early yet for me to have results, but I'm extremely happy I'm not taking the drug, and at least I will be able to feel I tried everything if it doesn't work. The longer you wait, the less it can help you. Duta is better, so if you want to switch to that I encourage you to do so, you are around the point where you might start seeing results now, but it can take over a year.