I am a bit of maniaco, but i feel that “generic” defences models don’t suit some factions.
So… How illegal would be , tournament side speaking, ( at home i can use a coke can as tower 
) personalize from scratch a few defences for my factions? Eg for dusk those are too “clean and primitives” so i can see more fitting a soul sweeper pit or an arcane device instead of trap pit and barrel, for instance. I can convert the First but the second should be built from scratch .
Idem for towers, maybe i can add on the original but feel something more arcane built from scratch can be Better. What do you think? Can i be obliged to have a reserve of " legal object x" or can i go with converted( for sure) /scratchbuilt ( not so sure) for official tournament event?