10-12 lbs naturally is a big feat, but with your calorie surplus and training it very well can be done over the course of time. My only advice is now that youve found the sweet spot in your nutrition, keep an eye on it. When you start slowing down gradually increase calories and assess. As long as you are progressively gaining though you are hitting your goals and should be patient. Far too many times people dirty bulk in an effort to gain 10lbs, and wind up gaining 15lbs and 4 of that is muscle hahah. With your clean eating and surplus you are well on your way. Keep us posted!