One of the reasons for the mistake with Russells sweet, that males were not needed is that a couple of grafted trees (with overgrown male rootstock) had masses of large fruit to the extent that branches were breaking.The overgrown male rootstocks were overlooked.The taste keeps being described as like an excellent peach and unlike other Garcinias.While I have a 3 feet high female I have lined up either a grafted male or a bit of a male to graft onto the one I have.
With regard to G.dulcis, I found it hard to tell apart sour dulcis and line of G.xanthochymus from the fruit appearance and flavor.