you really need to match the diameter of the sizing ring to the diameter of the chamber you are shooting that round in to have the post sizing ring work the way it was intended.
really the question you need to ask yourself is what is my maximum tolerance and make sure the ring is no larger.
in your case you need to use cases .009 in thickness or less or ream out the inside diameter of the sizing ring to closer match your needs.
the whole point of the sizing ring is to make sure nothing larger than the post sizing ring enters your chamber, which in theory leads to more reliability in feeding.
You may be right, but I took a much easier approach. "Ever try to hone out a carbine cylinder with equipment found in the home workshop, even a home workshop equipped with a metal lathe and a small vertical mill?" Yes, I have "green wheels" but they are 6" or more in diameter and are made for use on a surface grinder, not an ID/OD grinder used on a lathe.
My solution after fighting with the FCD for maybe 6 months was to put a string tag on it identifying it as a 45 ACP Lee FCD and placing it in one of many drawers holding unused misc. stuff accumulated over 55 of collecting guns and gun related parts and tooling for my kids to wonder "What the he!! did Dad use this thing for" sometime in the distant future I hope.
Then to return to my original die sets and tweak the settings till I had a set up that worked for each and every gun, then make up dummy rounds for each particular bullet fired in each gun and label them so said seating could be returned to. All problems were and are solved in all my pistols chambered for the 45 ACP round, This encludes my Llama MaxI, Springfield S/S, Kimber S/S custom and my Ed Brown with match barrel.
Being as I never had a FCD die for any other caliber I have been one of those who have loaded thousands and thousands of 9 MM rounds in my pistols chambered for that round with no issues occurring. Must have been to dumb or maybe to stubborn to know my failings. This is my experience in 20 - 25 different pistols chambered for 9 MM.
The same applies to 32 ACP, 380 ACP, 9 MM Largo, 38 Spec, 357 Mag., and any other handgun caliber I reload for that I might have missed, after all it is 2:30 AM.
Best to all, If you wish to use the Lee FCD, have at it, personally I see nor have no need for it.
BTW, My feedings problems are zip to none in any of my handguns nor is the problems with leading when I returned to the so called "old" way of accomplishing my seating and crimping using the "old" system.
Maybe I'm an old fool, but I'm a Happy Old Fool.
And ALL of the above works just fine for me, Thank You Very Much.