It's best not to RAID any SSDs at all: You will only completely defeat the TRIM feature (especially if the controller that the SSDs are connected to does not support TRIM when the SSDs are RAIDed), which means that performance will degrade much more severely than if the SSDs aren't RAIDed at all. In fact, under this lack of TRIM, your system's disk I/O performance may actually be much slower in RAID 0 than not RAIDed at all.
While it is true that RAIDed SSD don;t support TRIM, most have a process called garbage collection in place that functions similar to TRIM. I ha e had a set of RAIDed drives on my system for some time and haven't seen any performance slowdown. Of course, SSDs are very fast in case and I don't benchmark the drives often. Garbage collection is kind of a mysterious process in that manufactures don't talk too much about it. I do know it usually takes place when drives are idle, so if your drives are constantly loaded, then it might not be a good idea to use RAID.