Claybuster, as usual you have good taste in shells - the Federal GMI shells are my favourite. The last time I chrono'ed them through my 30 inch barrels they were going 1325 fps though, not 1400. Recoil is very mild with these loads.
You are also spot on with your observation that the international shells use better shot. This is the key to all top flight loads - hard, round shot equals better patterns.
While I regularly use 1 1/8 oz. loads while hunting (12 gauge) it has been a long time since I used that much lead on a clay target.
A fellow showed up at our range a few weeks ago and when he started shooting the 3 foot flames and cannon - like report instantly brought the attention of the range manager. After inspecting the loads, it turned out that they were factory Federal shells using 1 1/8 oz. of lead shot, at an advertised speed of 1500 fps. Perfectly legal according to club rules, but annoying as hell - they were really loud. I have never seen lead shot factory loads claim that much velocity, but I believe they must be close to that just from the noise alone. He claimed he bought them at Wholesale Sports. Maybe I should get some, just to throw everyone off their game at the sporting clays course.
Sharptail