In reply to some of your suggestions...
I'm not going to go the dedicated upper route due in part to the cost, but more because I want to train with the optics and so on that are on my .223 upper. I want, as much as possible, to practice with the set up as close as possible to that of how I shoot with the .223 ammo. I realize there will be some accuracy issues using the EOTech I have sighted in for .223 with the .22LR rounds, but if the targeting is not vastly off, at least I'll be in the habit of using my regular set up and not having to sight the gun in a new each time I change between calibers.
It is interesting to read that the Stag Arms kit is made by CMMG. It is vastly less expensive, yet still stainless steel. Nice to get the feedback that it worked well, but can you elaborate on "the little plastic piece prevented the ammo from loading"? I'm not seeing what you may be referring to when looking at a picture of the kit. Was is simply removed and then you used the kit without that piece?
Shootniron, the CMMG kit that you have that has worked so well for you, is it stainless or blued?
So far, I'm leaning toward the Stag Arms kit but please keep the feedback, suggestions and recommendations coming.