How to run a founder dinner people remember

Curation is the whole thing
Nobody remembers the restaurant. They remember who was across from them. The hours you spend deciding who to invite are worth more than everything you will spend on the evening itself, and they are the part most hosts rush.
Keep the table small enough for one conversation
Past a certain size a table stops being a dinner and becomes several parallel dinners with bad acoustics. If you cannot hear the far end, you have built a room, not a table. Smaller than feels efficient is usually right.
Do the introductions yourself
You know why each person is there. Nobody else does. Two sentences from the host about why these two should talk will do more than an hour of unassisted mingling, because you are supplying the context that strangers cannot.
Stay at the center of what you built
The reason to host is that you become the connective tissue of a group that would not otherwise exist. That only compounds if the group persists between dinners. Otherwise each evening starts over, and the network you are assembling never accumulates.