Override Addon Mail Template

I've done this for other things, but not an addon template (that I can recall).

I'm trying to override the template file:


I'm using an override path of:


I've cleared the registry and template caches via &cc&ctpl but the override template is not being seen.

Anyone see where I'm astray?

Grr... Never mind, I had the new template editor configured.

So I guess my next question is. They now seem to set snippets in the addon.xml file under a tag.

If I add that to my addon.xml and have priorities set that my addon is loaded after the vendor_plans, will those snippets override the ones in the vendor_plans addon that have the same names? Or will this double them up because they are addon specific?