Well his RH is excellent, as you can see from his facility with it, and as I have mentioned earlier in this post, as long as it is not causing your RH to close up significantly internally and creating tension, it is not such an issue as you may have been led to believe.
The existence of this tendency does not mean that the hand cannot do the job required of it in every situation.
It is still well worth your time to closely observe his RH technique keeping in my mind that you have a different anatomy and in the end you have to resolve the issues for yourself and yes it does take time probably longer than the 6-12 month period you have mentioned.
I think it took me 10 years to establish my posture and technique and of course it still develops to this day although I do not play classical guitar nearly as much as I used to once.
is never a word I like to use preferring the term excellence!
Persevere my friend and you will be richly rewarded!