So just to check, the method that metroid maniac is very kindly employing for people uses the account swapping method detailed in post #1? Which means it will require a separate memory card and account to the primary one?
I can do either the account sharing method or the account swapping method.
The account sharing method means I temporarily need access to your primary account, but it means you can keep your bubble on your main memory card with your main account alongside your regular content.
The account swapping method means I generate a secondary account, and your custom bubble will be associated with that account. So you must either use reformat your Vita whenever you want to use your custom bubble or use a second memory card.