Shopify Buy Button - how to change default quantity of product

Hey all, on an external site implementing the Shopify BuyButton.js which has an immediate ‘go to checkout’ button and clicking on it will add a single product to the Shopify cart with a quantity of 1. I need the capability to change that quantity value to a custom value, but I cannot figure out how to change the default value of 1.

This is the closest solution I could find, and tried, but it did not change my quantity when it went directly to the Shopify checkout. It could be that the additions tried here were adding to cart, and my buy button is set to go directly to the checkout.

https://stackoverflow.com/questions/44683058/shopify-buy-button-minimum-quantity

Like the user in that post, I have tried several things (manipulating the DOM after it finishes, trying events, trying to find one of the options that works with the URL below) but I cannot get that quantity to be -not- one/1

There are very few examples in this documentation and even in the blog. If anyone can let me know how to make this happen, that would be great. Here is the Shopify BuyButton.js without any of my attempts in it.


Thanks much!