i don't use a ventilation fan,just a 16" standard fan with a hose attached to the back drawing cold air from outside,which i sit in front of the wardrobe then close the doors onto it so during the light time i have a 4" gap in the doors,with the blades of the fan inside the doors

on a brighter note last night humidity only reached 62%,i've grown succesfully in there with similar humidity in the past so hope it'll be ok

i'll remove the shelf but only if totally necessary as it becomes just a box and not a very steady box at that,that shelf seems to strengthen it,plus the fact i'll need to rehang lights and put more foil tape up etc,i seem to remember worrying a lot 2 grows ago about height but all was good,plant reached almost 3 feet and fitted ok,with worse ventilation than i have now