If I am still correct (I haven't looked into this in a long time) initial loading is based on total vars in addonpackages, but overall performance is based on how many *morphs* are in those vars/ in your custom folder.Did vam works slower if more vars inside (got 700gb addonpackage) size and vam load much slower
So you wanna cut out as many morphs as possible, even if they aren't preloaded, they are always being calculated.
So good rule is just have few addon packages, more specifically have fewer *morphs*.
if I am wrong about this *please* reply to this, I haven't looked into this in a while and would love to find more performance tweaks.