Hi Sean.
You could use the free RSVP tickets from Event Tickets free/core plugin if tickets are in limited supply but do not have a cost.
It sounds like they do have a cost, in which case Event Tickets Plus would be required (which you already own) and you could setup whatever payment methods you want in your eCommerce plugin (e.g. WooCommerce Checque payment). However, ticket stock (how many tickets are remaining) do not get updated until your eCommerce plugin’s checkout status is something like “Completed” (not just Pending Payment sort of status). In other words, you’d have to manually change each order’s status from Pending to Completed in order for the available tickets to appear as though one less ticket is now available.
I hope all that made sense.
Anyway, please reference theĀ Tickets: Managing your orders and attendees KB article for information about Attendees reports that you could use offline. We also have QR Code Checkins if you want that functionality!
Please let me know how things go for you.