i would go with the tangs.
p. demasoni are very territorial and aggressive. they are very defensive of their territory. the size of the fish does not matter to the demasoni. they also do not like even their own kind near their territories. the best decor for these fish is rockwork. i could sit for hours and watch these fish. they go in and out of caves and crevices in the rock work. at first i thought they were looking for new territories, but the established ones will also do it. they are just very curious fish. like to explore their surroundings.
another interesting thing about p. demasoni is they do not like to expose their ventral side. they will turn into contortionists to keep their ventral side covered. for this reason the higher the rockwork the higher the demasoni will go in the tank. they will stick close to rockwork, plants, substrate so as not to expose themselves.
these are one of the rare species of mbuna that is not best kept in overstocked tanks as they will kill anything that ventures into it's territory.
