limit the spread of IPNS to a restricted number of peers
Not really, but it doesn’t sound like what you actually want to do.
to get instant updates from my IPNS
I think the easiest way to do something like this is to utilize IPNS over PubSub. If the peers are in the pubsub channel (i.e. they’ve searched for your record recently) then they will receive the updates almost immediately. Note that the upcoming go-ipfs 0.5.0 has some improvements to IPNS over PubSub that make it even fast on initial use.
so I don’t want to have to wait to spread to the entire network to get a confirmation
Currently the IPNS publishing command waits to publish to both the DHT and PubSub (if PubSub is enabled) so the return will look slow. However, users will get the update over PubSub as soon as it reaches them.