You are exactly right about picking up an extra bird or two. You will see, on the scoreboard, that more often than not one bird separates HOA, or high in class, from first place loser. I'm a firm believer in working to get every bird you can.
The Interceptors work very well for me, for that. I'm not saying they are better than changing chokes, but just easier for me, and less thinking involved. In my gun they open the pattern just as much as the homemade spreaders I have loaded, but still give me a nice pattern without a lot of patchiness and holes. I'd say they open it from a MOD pattern to a light IC. That's a pretty nice increase in size.
One of my shooting buddies, and toughest competitor on an everyday basis, shoots -.005" spreader tubes at almost everything, unless it is a very long bird. He seldom gets hard breaks unless the target is very close, but I can't argue with the results. It's just not my "cup of tea". He breaks targets on edge with those "negatives" so far that I sometimes can't believe what I'm seeing.
Best to ya'. SRH