If you fly a symmetric off the bow you will end up with nothing particularly good going on, the sail will be twisted and mis-shapen with no shoulders. The sail is not likely to draw, and if you can get flow over it, it may not do much more than pull laterally. Asymms and symmetrics have very different profiles and shapes.
If you want give to, it a try in light air, but I don't think the end result will be very serviceable.
I second that! Square peg in round hole comes to mind. Having raced J105's, J90's, Nelson Marek's and a few other asymm friendly boats, you just can't make a symm spinnaker work properly without the pole. Just do a little research on the dynamics of each.
I actually re-rigged my Beneteau 473 for a symmetrical spinnaker because I knew it would vastly improve the performance of this Groupe Finot (read, Vendee Globe lineage) designed boat when sailing anywhere from a beam reach to running. Although I have both kite types on board, we flew the symm the entire 750 miles from San Diego to Cabo almost entirely on rhumb line. There were quite a few faster boats that fly asymms that came in after us. We had both weapons on board and chose wisely!
So, no, don't bother. It'll be a mess. You might look for a local J24 or J105 fleet and see if you can get on board. Race some beer can regattas to get a feel for how things work. That's the best way to fully understand the dynamics of the asymm kite.
Lastly, if you choose to fly a symm kite, just get a pole that is equal to your "J" measurement (horizontal length from mast to headstay). Once you have everything rigged properly, go out and enjoy sailing at its best (read, asymms are too easy ;-)