In my note to Jean I did say that I thought this one was made an easy choice by the incredible fine art stamps issued in March.
The stamps are relatively large, so the great thing about the article this envelope was made from is the large amount of white space (now well-aged off-white) to accommodate it. I also love the running hare painting by Colin Finn (no relation to FinnBadger, sadly).
Here is the sealed envelope with the stamp:
I attempted to mimic the captions on the paintings for the address.
In hindsight the stamp should have been lower down with the address above it, like painting 14. I was thrown off by painting 15, and I think I am still too fixated on having the address too central. Must use other part of brain more. I also opted for clear labels. They aren't 100% transparent, but better than bright white for my purposes.
I might need to find an envelope that doesn't require a slanted address next time - Jean is going to think I'm a one-trick pony.
I didn't add additional postage, so I hope there wasn't too much delay in delivery.
Edit: it arrived unscathed. See Jean's response.