If you take glutony of 7s and turn it back, you will have 5s avaricity ( avaricia is in spanish but i dont know if im right)
It's like seeing the world as too big, too strong, too intimidating, and they consider so small. The difference between 6s is that they naturaly choose to recluse, they dont actually try to conect with the world ( with Sp last and Sx first this may be less visible, but they really feel it) it's an existensial fear to keep the little energy that they think to have to themselves.
This is true even for a Sx/So 5. Doesn't merely have to do wwith insctint is more than that.
This is interesting. I had always considered 5's avarice and 5's emptiness as two separate things. I see "avarice" rather as a consequence of the obsession with ratonality and logic: "I don't want to spend money on that, because it's unneccessary" "I don't want to waste words because I've said everything I needed to say", etc...While other people don't mind wasting resources for the fun of it, 5's will do it only if there's a logical reason for doing it. At least that's how I see it.
Emptiness for me means rather the disconnection from the inner-self. You keep your head busy with dry theoretical problems and forget about yourself.
In this way, 2's, 3's, 5's and 7's, all of them can become empty if they're not careful, because of different reasons.