I'm not sure why you think there will be problems.
1. How many users?
2. How many transactions?
Is the information the same for ALL USERS or is it specific PER USER or is it specific PER SESSION?
Same for All Users: Could store in a datatable or a Thing's Property
Specific per User: Make it a User Extension (edit ThingShape UserExtensions) - access information from the Users Tab in the Mashup or use the CurrentSessionInfo Resource
Specific per Session: Create your own ThingShape with the necessary property and add it to the session by adding it in User Management Subsystem
You can then access this information on the Session Tab in the Mashup or use the CurrentSessionInfo Resource
If there truly is a very heavy load / lots of traffic User or Session certainly will help reduce that.
Also see the documentation on Session Parameters here: Session Parameters
If you're storing an infotable on a thing, you're better served by changing your design so that you're storing the data in a data table--especially if it's sensitive data that you don't want to risk losing. There are a few threads about how to properly write data to a thing's infotable property without losing your data. Just something to keep in mind. But when the data is in a data table, it's easy to update. You can also implement a pseudo-version control so that if someone accidentally changes a row, you can easily roll back.