Shooting Skeet is a great idea. It is more like typical wingshooting. The Skeet field will teach you allot including following through with your shot and never stoping the gun. Trap would also be a good idea as most pheasants you shoot will come up right in front of you and go away.
Sporting clays is so far removed from actual hunting situations. The clays are faster than anything you will ever shoot in the wild. The leads on breaking some of these targets are exagerated to 10-14 ft.
Remeber no matter what you shoot trap/skeet/sporting clays. What it takes to break a target will not necesarly kill a bird. Always be in front of your target
For shooting preserve pheasant you can use a skeet or IC with no problem. Don't even have to use high powered shells. Dove loads will get them just fine.
When wild pheasant hunting use your IC with a high power load
3 3/4 1 1/4 #6 besides, hopefully you want be shooting at anything over 40 yds away.