Reviving this old topic, rather than starting a new one. I hope the OP doesn't mind!
I'm thinking about doing the same thing here where we live in central Brazil. We're finishing our house and have just a perimeter fence, but now the neighbours are building in a location where they'll have an unobstructed view of the main bedroom. My wife is a bit concerned.
I have some young trees planted about 3m from the fence, evenly spaced about 5 metres apart (cashew, Brazilian pepper tree, and some others). I have 4 or 5 Garcinias that need to be planted (all between 2 and 4 feet tall)... could I squeeze these in between the others, slightly offset, to create the hedge she's looking for? The trees I have are either G. brasiliensis or gardneriana.
echinopora, did you end up trying growing them together?
Thanks!
Brad