I finally came up with a menthol I like. It's mostly my ADV. Of course, plug these figures into the calculator of your choice, adding your own nicotine beginning and ending strengths. I know you know that, but my left-thinking analytical brain made me say it anyway
Cowboy Blend 2%
Menthol 3.5%
Marshmallow 1%
Pharmacy Saline (0.9% solution) 2%
Spearmint 1 drop/10ml
Seems like the tiny bit of salt in the saline solution makes the flavors brighten just a bit, and it doesn't need steeping, at least for me. I make it at about 10mg nicotine and 50PG/50VG. I guess you could use just distilled water, but I don't know if it would be the same. Also, I use a back rub massager for shaking my juice, and it shakes it so well, it's cloudy for a little while from all the almost microscopic bubbles in it. Don't know if that mixes it so well it doesn't need steeping, not sure...
Another one I make for my granddaughter's boyfriend doesn't have any tobacco flavoring, and it seems like it would be too sweet for me, but he likes it. It's basically a cotton candy juice with spearmint flavoring:
Ethyl Maltol 10%
Spearmint 1 drop/10ml
Again, 50PG/50VG, but he wants it at 24mg nicotine.
Be forewarned, spearmint is VERY strong, so approach with caution in batches smaller than 10ml.