I did mine last week, for nothing, as my old one did not have a broken diaphragm , but still I can probably bring few points to this DIY
This is for 2001 C2
1: Lower the engine with a jack underneath as much as it goes, eventually it will sit on the crossmember and the jack won't bare any weight. I still used bunch of jack stands by precaution. I did not unplug anything prior to lowering.
2: Work from top most of the time, Keep alternator in place. Use 1/4" air ratchet for most of the work
3: and probably the most helpful - to put the provided clamp back, first use Clamp plier