Good question, I do not know the answer to it. So at least you could printenv in prom before you start the process. Write down or copy/pasta if you are on serial console. I followed the procedure listed here
I try to get them out quickly, but due to Coronavirus I'm usually only going to the post office once a week, usually Wednesdays. So, if you put your order in first thing on a Wednesday, there's a decent chance it'll ship the same dayNow that was some quick shipping! Haven't tried them yet, but have faith they'll work great when I need them.
Thank you for the URL: I bought them bothThe Tindie link says 2 left in stock...