I was playing with PlayonLinux 5 and was unable to find a way to install a 64-bit prefix. It is possible to install 64-bit Wine engines, but how to specify a 64-bit container? Thanks in advance.
You can find a description in the GitHub wiki: https://github.com/PlayOnLinux/Scripts/wiki/script.js#advanced (see "wineArchitecture"). In general, it's a good idea to ask this kind of questions on GitHub (https://github.com/PlayOnLinux/Scripts) because we'll be notified about them there.