My recommendation is to use the latest version of the chart, 0.16.1 and then override the vault version you want to deploy. The major note I’d give you is that a pick a major version (1.6 is the oldest version supported) but don’t deploy 1.6.1, 16.7 is the latest release in that train. There are security and patches that are applied to in between releases that should be used.
Auto unseal no issue – I’d move away from Dynamo and to Integrated storage though – much faster access and a lot less I/O overhead. If you’re willing to upgrade and are willing of switching to Integrated Storage, then 1.8 is well worth the upgrade (1.8.5 I believe just got released).
There are notes in the upgrade plan on upgrading multiple major versions so do read them carefully.