Two SanDisk SSDs, what should I put on which?

After having sent my Ultra Plus (128GB) to support, I got an Ultra II back. Though, I also bought a SSD Plus (240 GB) since I was lacking space for my games and software, and now I've got two SSDs. What should I put on which ? The difference may not be noticeable but I'd want to be sure.

I have games to install (Windows also, of course, which is currently on the SSD Plus, but moving it is possible), Visual Studio, Unreal Engine 4, common office software and all the rest (programming tools, TeamSpeak, Steam...).

Is there anything I should care about or do both have the same performances ? I don't really plan to store files on my SSDs (since I also have an 1TB HDD), except maybe Unreal project files and assets.

Thanks