As I said before...I look at it the other way round..On Heavy Ground he was only 2.6seconds faster than the Juvenile hurdle on the same card
On Good to soft ground he was 6 and 7 seconds faster than 2 handicap hurdle winners carrying less weight than him on the day.
That surely indicates he at least as good on good to soft
I agree you wouldn't want to run him on fast ground but where is he going to encounter that these days?