With some savvy planning you could probably fit a lot of trees together, place trees, in a way that smaller varieties are in front ( facing the sun ) then progressively larger trees to the back, you want to minimize shading for most trees, Most Garcinias really need shade for the first few years.
In Mango plantations that use high density technique, mangoes are spaced just 6-8ft apart, and kept under 13ft high.
Another option, I was just thinking about, you could just grow everything in containers, this will allow you to move them around. and adjust the spacing, as some tree will grow faster others slower. plus container growing will dwarf most trees naturally.