You can use two quick links to insert the extra links you need for the 11-34T cassette, then remove it to shorten the chain for the 11-30T cassette. Then you'll have the right chain length for each cassette, and it's very easy to change between them.
Didn't think about that. And assume this wouldn't lead to any catastrophic outcomes on the road. Mind you, those links ain't cheap, but cheaper than getting two 11-34 cassettes and a new chain
Cheers. I was wondering if there was a solution that didn't require breaking my current chain