One larger group of Corydoras instead of two groups of six will look nicer and get a more natural behaviour, but would they be at risk in a 100cm tank, that has caves for the Apistogramma hareem spread out across the tank floor?
I'm also looking at other members that have the same size tank and similar set ups including the peppers and apisto/rams
and they dint seem to have problems, maybe it just me....