Well, I'm not sure about the offset. But I found an EBOOT a while back with super force host. (not sure who I got it from, I'd leave credit if I did.)
DL:
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and from what I remember, I tried to get the dvar to work a while back. It's something like:
party_host "1"
party_iAmHost "1"
party_connectToOthers "0"
but I think the 'party_iAmHost "1" was read only.
Sorry all this a little vague, but maybe the eboot will reveal the offset.