Can I take a MemberStack attribute and use it on a script that changes the URL of an iframe?

I have a photography studio that I rent out by the hour. I recently implemented memberstack to our website and want to see if I can help our users skip a few steps on checkout and also keep them from sharing memberships. The scheduling software we use, Acuity Scheduling, allows us to pre-fill user information straight from the url. The booking date selector/checkout page is just an embedded iframe on our website that is gated to members. 

The way that I'm thinking this can be done is the following

1. When a member signs up, the info goes to Airtable where a formula automates the pre-fill string that would go at the end of the iframe url.
2. This string becomes a MemberStack attribute and i have it load somewhere in the background of the booking page.
3. (This is where my coding knowledge runs out) I run some type of script that takes this unique pre-fill string, searches for the iframe url, and tacks it to the end of it before it loads so that the information is filled in.

Is this even possible? A note is that we have multiple locations, so the studios are CMS items with the embed codes being a added to a rich text field.