Hello! In theory, CBT reset should not be required as long as you manage to perform the upgrade in a way that snapshots are not created on VMs running on vSphere 6 before the patch is installed. Honestly, if I were you, I would just wait for vSphere 6 Update 1b (or whatever) that incorporates the fix. This will make it much easier to upgrade to, and the CBT fix itself will be much better tested by then.
But then again, rumor goes that this new build will be out on the second week of December only, so think twice if you want to start the upgrade as soon as it is available, and then potentially ruin your Christmas holidays