I make a lot of custom listings (I'd say about 2/3 of my business is custom listings)
I always put a descriptive title and tags - even if the listing is only live for a half hour that's still another way someone could search for something similar to that item and find you.
i also put in the description any details that my customer and i have discussed prior,, just so i don't miss anything when i go to make the bag. that and they can confirm that the listing itemizes exactly what they want.
and that's a GREAT tip about the "if you would like a custom listing please convo me" I hadnt thought of that before, mind if i borrow? :)
hope this helps!