I've fished this stretch a couple of times upto Bykasein at different times of the year, April and October. However, I haven't managed to land a fish onthe fly although to be honest I haven't spent a lot of time oon the fly - as you say the lure and also deadbait/atta techniques have produced. But I'm not going to give up the fly due to the attraction of playing a mahseer (any mahseer!) on the fly really excites me!
We have caught Indian Trout though, which are lovely looking fish.
I have mainly used a floating line and flies such as Wolly buggers, Blackamoor, stonefly nymph, Salmon files like willie gunn. allys shrimp also fry patterns. I even tried Bone fish patterns like crab ( great bait if you can find them).
I'll be packing the fly kit next time I go, hoepfully next October, I've alot of unfinished business inhte North:)
Good luck, I'd be very intereested to hear how you fare if you try the fly.