It’s not a stack but it will work with your site. I have used Sitelok (years ago) in conjunction with a members area. You should be able to setup access for your printers to “grab” the addresses I believe.
Search the forums here for “sitelok” and be sure to read the details on the sitelok page. On the sitelok page there is a link to download a Manual PLUS a short manual for RapidWeaver 7. Not sure if it’s been tested with RW8.
Sitelok people pop into the forums here now and again. I believe they are well respected and trusting with RW users.
Don’t confuse “Sitelok” with “SiteLock” which is a completely different animal. You want https://www.vibralogix.com/sitelokpw/
I’ll also add that Joe Workman as a stack especially for SiteLok… I don’t think it adds any features, it makes it easier to install and setup I think…I’ve never used it. https://joeworkman.net/rapidweaver/stacks/sitelok/
And check SiteLok’s plugins page. They make plugins for many PayPal, email systems, carts, etc.