you would create a filter {#p: your pubkey, kinds: 3} which would only get contact lists that you are on. Then you would have to keep state to not count duplicates
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Got it, so then the relays would only serve up kind 3 requests that actually contain your npub, so your client doesn't have to look at every single kind 3 in existence each time it checks for follower updates, but it's still a massive amount of data to have to download every time it checks for updates, and that would need to be stored locally to avoid double-counting.
Yeah, not something that is realistic on a mobile client without a server that can do it off-device.
Thank you good sirs ! Appreciate your replies