Imperial Armor Book' units in a tournament

[Blackcloud6]

I'm hosting a small three round 900 point/army tournament where players win by overall total points scored in all their games.

The Army must be a Combined Arms Detachment from current codices/supplements. I am not allowing Lords of War, Apocalypse, Horus Heresy, 30K units/models.

What are thoughts on allowing Forgeworld Imperial Armor armies? I'm not too familiar with these and there are so many IA books that my head spins.

I have one player requesting to use Renegades from Volume 13.

So, what do you guys think; should I allow it? Are there potential issues others may bring up? Or am I worried about nothing?

Thanks for your help.