I threw them in the same bucket which is "below ATG level but were great servants for their country". Here's what I said:
There's quite clearly a huge spectrum and maybe you could split a whole bunch of players. Zaheer would be at the bottom of that pile and Walsh at the top (though TBF maybe I'm slightly underrating him because I mostly watched him against Australia). You don't get 300 test wickets while being complete and utter garbage. That's something only 24 pace bowlers in history have managed.
Whether you place Walsh at the bottom of the ATG tree or at the top of the ATVG tree is largely a matter of how many players you put in each category.
Frankly though, there are 20 or more bowlers in history I'd have ahead of Walsh. From the top of my head - Marshall, Ambrose, Garner, Holding, Croft, Roberts, Bishop, Hadlee, Donald, Pollock, Steyn, Philander, Trueman, Statham, McGrath, Lillee, Davidson, Lindwall, Wasim, Waqar and Imran. There are a few others like Reid and Harris who had quite short careers but were better while they played who I wouldn't consider to be ATG. Walsh is somewhere in the mix with those guys for me.