I think it's trial and error, I have had the vast majority of his content installed in my TS09 SP4 since January 2013 and it shows as build 2.9, even some of his new scenery such as the houses, etc, are OK, however, I note that both of his Evans Hoppers Packs have now been updated to build 3.4, so, I don't know what else he's changed recently, you can amend the config.txt to show build 2.9, but, as to whether they actually show up in your game, I haven't tested that out as yet.
Cheerz. ex-railwayman.
