If you are considering going for a non standard PRSA at any stage then you should only do so if there is a clear reason to do so particularly since some non standard PRSAs can charge more than standard PRSA and, specifically, more than the 1%/5% capped charges that apply to the latter. As far as I can see non standard PRSAs in general don't really offer much to justify paying more for them.
You can have as many pensions as you want (PRSAs, personal pension plans, occupational funds etc.) but, in general, you can only contribute to one at any one time or at least only claim tax/PRSI relief on contributions to one at any one time.