Malathy,
I recommend you the Jeff´s paper:
There you have a chapter for ssd disks. However this question depends on database size but for a 300 gb database a 30 gb device perhaps will be good enough not to suffer contention in devices always its better to paralelize. Also look after dbcc tune to logs devices in order to let hk make a big write on it. I don´t think that you will have an improvement on reads (data segments).
I hope this help.
Javier.