Where are you shooting? Each club is built like a golf course - so while a trap or skeet field is exactly the same everywhere, the OPPOSITE is true when it comes to sporting clays courses.
If targets are close, under 25 yards - SK and IC is all you need
Check out the chart from Briley - it will give you some good ideas - don't worry about changing chokes from one station to the next - done all the time. I carry in my bag:2SK, 2IC, 1LM, 1M, 1IM, and 1F
http://www.briley.com/2009/sportingclays.html
As you can see from Briley's chart, most target presentations are using a recommendation of fairly open chokes. I typically start with IC/IC and loosen or tighten as I think I need to be. Since I shoot light 7/8oz loads, I want my chokes to be one .005 constriction tighter than what folks using 1oz or 1-1/8 oz use
All you need is 1oz or less at around 1200 fps - heavier and faster loads, especially the promos, can beat up over the long haul, leading to fatigue towards the end
Good Luck, welcome to an addiction that makes crack cocaine looks like sugar pills
P.S. - if you are using a semi, start with an IC - should be good for 80% of the typical targets at a typical course (not a registered shoot with the big boys).
Remember also sporting is about trying to hit as many as you can - 80-90 is an excellent score for the big boys, so do not despair if it doesn't not match your typical trap or skeet score - it isn't supposed to