Nice gloves. I have a different glove in kangaroo leather, and love it.
Based on my experience, the only sure way to get the size you want is to try them on.
I sent in a trace of my hand. One finger was way too big. Sent it back with a new trace. Same finger was way too small. I wound up giving it away.
Trying them on at an event, the sizes could vary a lot. With some a large was too big, others an XL was too small.
Not a knock on AL. Leather is an inconsistent medium to work with. Different sewers will vary a bit. And I'm very picky about how my glove fits.
I bought another, but only after I could try it on first.