If you do a fresh install, then you don't require a second SSD.
Only if you want to transfer the exysting RAID0 installation to a SSD, might you need a second SSD in a RAID0 array. The benefits of that are questioned by many.
Again, I emphasize this is an unknown area for me. If it was me : I would do a clean install of everything, and forgo or forget about a RAID0 setup for the OS and installed programs altogether.
A single SSD is lighting fast compared to most home-RAID0 setups anyway.