The Tarantula is not really a great edging shoe, which might be part of your problem. It's also a velcro shoe, which generally won't cinch down as tight.
Anasazi V2 lace-ups have a reputation for being narrow in the toe-box, which might be perfect for you. They also might be the best edging shoes ever. Muiras are lace-up and while not exceptionally narrow, edge quite well and stretch about half a size. So, you could size them down a little and let them stretch more lengthwise.
TC Pros are another contendor based on what I've heard about fit, but I haven't used them. If you can find them they are worth trying on.
I'm surprised you found the Crux to be narrow. Usually Scarpa are rather wide.
Used Guide Tennies (with the X on the back, not the 5.10 block logo) had a narrow fit. Newer ones are more of a regular D width.
What are you using the approach shoes for? It's easy to find running shoes in narrow widths (NB), and you can get a worn-down pair and put C4 rubber on the bottom. Or, just approach in running shoes.