Only two chokes ? Anyway you ALWAYS use a choke otherwise you will damage the the choke threads on the barrel.There are many chokes available ;cylinder,improved cylinder,modified, improved modified, full, extra full.These are listed in order from most open pattern to tightest pattern. For skeet you would use probably the IC choke, for trap maybe modified....Since you are new to shotguns I strongly suggest you get lessons from a good instructor, it will greatly shorten the learning curve.