Hi there!
I am trying to add size availability for the collections pages on the Prestige theme.
The following images are what I mean
I believe both those images were on Presitge theme stores.
Sorry you are facing this issue, it would be my pleasure to help you.
Welcome to the Shopify community! 
Thanks for your good question.
Please share your site URL,
I will check out the issue and provide you a solution here.
Here are the sites of the examples: https://www.buffbunny.com/collections/shop-all , https://threenailsclothing.com/collections/mens
and my site is https://blastedvfx.myshopify.com (has password as I haven’t launched)
Thanks!
Hi, BlastedFX
When you add product, you can add the product size in option var.
I know that, but I want to get it displayed on the collection page.
@BlastedFX - we need to edit the variant code to put product sizes on collection pages. I recommend to duplicate your theme as backup, work on it and once variants are put on collection page then make it live. or I can help you to do this code edit.
I am sorry.
It will have to change the code in ‘collection-template.liquid’
It’s a bit complicated, so it’s difficult to explain here.
If you want work with me, I can change the code of your site.
And I can support about other problems.
Thanks.
Would you be able to help with the code?
@BlastedFX - yes I can help you with the code, can you add me as collaborator? so I will send request