This was helpful for me, thank you!
I needed to change <Track> to <Track#> to get it to work for me. I also added a function to exclude track numbers if they are not specified.
$If(<Album Artist>="Various Artists",Compilations,<Album Artist>)\<Album>\$IsNull(<Disc Count>,,$If(<Disc Count>=1,,<Disc#>-))$IsNull(<Track#>,,<Track#>) <Title>