.... I’ve always instinctively felt, like g3g6, that the Hippo must be inferior against the Austrian (and best against Nf3+Nc3+Bc4 setups). Why, I wonder, does Nigel Davies (on ChessPub) suggest the reverse?.....Probably Nigel need easy points from opponents...

Ohh, only joking

. My personal opinion is, that Hippor is inferior against Austrian. Strong players must found holes in black position - look at Dolmatov-Azmaiparashvili Elenite 1995.
But maybe 5 …b4 needs more examination? Re the system with 2 …d6, after 5 Nf3 Bb7 (5 …Nd7 will just transpose?) 6 Bd3, perhaps Black can strive to enter optimum lines with 6 …Nd7 or Suttles’s 6 …c5!? -? Maybe work is needed on this? – I freely admit I certainly haven’t done it!
Maybe yes, maybe no. All lines are for me too sophisticated.
Interesting to have your thoughts on the Gurgenidze, g3g6. In the Azmai-Gurg, I was aware of Cools-Khasimdzhanov but haven’t looked at this either. What do you think? I notice 9 Qd2 de (any good?) has also been played: 10 Ne5 and now 10 …Qa5, 10 …f6, 10 …Bf5.
Close to lost for black thought my computer and i agree.
10....Qa5 11.h3 Bc8 12.0-0-0 f5 13.d5 Nf7 14.Nf7 Kf7 15.Bd4 with attack
10....f6 11.d5 Qc7 12.Ng4 Ng4 13.Ne4 Ne3 14.Qe3 Na6 15.d6 Qb6 16.Nc5 0-0-0 17.de7 +-
10...Bf5 11.0-0-0 Qd8 12.h3 f6 13.g4 fe5 14.fe5 Ng4 15.hg4
10...Qc7, 10...Qd8 or 10...Bc8 i will analyze later.
9...Bf3 10.gf3 is too +/- as minimum
(As JEH says, so many paths!) As for the ‘Norwood’ [really the ‘Hodgson’?]-Gurg, I think MNb had some interesting ideas on this. 7 …e6 8 0-0 Ne7 9 Na4 Qc7 10 b3 may be the critical line?
Maybe later i will analyze this Norwood-Hodgson Gurgenidze. It's strange, that 4...Qb6 is not mentioned in Winning with the modern, but Dave play on ICC ONLY 4....Qb6 since 1997
g3g6