Hello Opapanax!
I've made a short search on google, and I found this Photo of Waris Singh:
He's probably an excellent actor, I've not seen the films you mentioned, but if you remember the story, Kusum is approx. 40, maybe 50 years old.
He has to make a serious make up to look older.
Otherwise... his eyes are too... gentle? In other words, he looks like a nice guy. Not like the terrific John Barrymore in Svengali!
I find it's very difficult to find the right actor for this character.
to be continued...
Ludovic