But with current SSD speed/size ratio this vulnerability window can be only a few minutes, also this can be minimized with mixing batches and vendors of drives.
Hopefully. . . though speaking of speed, there's another pitfall to be aware of: At present, very few RAID controllers support the TRIM command. On one that doesn't any SSDs plugged into it will slow down over time, perhaps becoming slower than magnetic disks.
Or just mixing intervals of memory installation; so you install the next SSD at half the life-span of the previous one.