I do this in my spare time, and the production rate is about one card per week. Unfortunately this means pretty long wait times and queues. In order to be able to manage the demand, I separate orders and potential orders as follows:
I try to keep the commissions queue limited at 2-3 months, while the wait list is several times larger.
I currently stopped adding people on the wait list, as it grew too large for me to realistically manage it. I will reopen it once I get caught up with my backlog.
If you want to skip the wait list, you can join my Patreon on the Commission Priority ($10) tier. This will give you access to the first open spot at the end of the commissions queue. You will be required to stay pledged until I finish your order, or for three months, whichever comes first.
If you want your order as soon as possible, you can pay a flat express fee (see Costs). I will make your card as soon as I receive the materials and ship it immediately after that.