Thanks for sharing. What is a 2285 doing playing that line? If he plays the Dragon, he should know to avoid 16...Nxh5. Even 15...hxg4 is now seen as a dubious plan, and most know to play the critical 15...a5.

In the second game, 21...Nc4 is the correct move. 

I play the soltis variation and against Karpov's move i think black needs to stay flexible as well. If white is going to make a prophalaxis move, so should black, and play Re8. Then after g4, hxg4, h5, Nxh5, Rxh5 gxh5, Qh2 black has Ng6, which uncovers the Rook on c5 onto the g5 bishop and helps to guard the kingside.

 Prophalaxis is always dangerous when white plays it in these lines. Most of the modern theory has Kb1 at some point and it seems to magnify the white attack.