No Heavy? Madness!
Seriously, might as well call this a "Hussar Duelling tournament" and promote it as such rather than claim (as the title suggests) that it covers a variety of cavalry types. If you want a cavalry tournament you really ought to enable at least heavies (important part of the NW cavalry community) and of course then ask players to specify which class they wish to play in their sign-up application (or maybe you want to leave them the option of switching, up to you).
Otherwise, you're alienating a significant number of heavy players and in particular some very good heavy players by only allowing hussars for an alleged "cavalry" tournament (not everybody makes a good hussar, it's a different approach than heavy after all) which means that you're excluding some of this community's great players from the fun.
P.S. WE SHALL NOT CEASE!