Yet another experiment? (Patreon)

Hello! I hope you like this month's pic!
I have an even more experiment for this page. I'm thinking to give patrons some kind of code you can redeem to get a guaranteed slot for commissioning me when I'm open. This some kind of code will only given to Grande and Venti Tier only via post, which later you can put/write on when my commission form goes online. This makes you can get a guaranteed chance to grab a slot on my commission openings, which happens to be in January 30th through February 3rd.

To be honest I want to give Tall tier a chance to get the code too, but it seems impossible (for example) 40+ patrons redeeming the code altogether to grab a slot, so for now I'm trying to give Grande and Venti tier first before. Please understand!

Also for security measures, the code will change each form opening. And also please do not spread the code outside our page. Keep it private among other patrons.

What do you think? I'm open for suggestion if possible.
Thank you and have a great day! 

Edit : after some suggestion, there will be a cooldown or 1 time only the code can be redeemed so everyone else can get the chance to grab the slot in the next opening. Also I'm not sure how to limit for patron slots if, let's say the forms are too much. Thanks for the input!