I reload .223 as well with a set of Lee Dies as well as an RCBS X-Die.
If these will be for an AR with lots of high-volume shooting, get an X-Die. The X-Die prevents case growth during the sizing process. One initial trim is all you need!
For case trimming, look at a Possum Hollow Kwick Case Trimmer. It chucks into a drill and works like a pencil sharpener. The adapter for the trimmer also fits an RCBS chamfer and deburring tool (which can also remove crimp).
For OAL, I generally seat/crimp to cannelure. For bullets without a cannelure, I load them long enough to fit in the magazine with some room for error, generally around 2.250".
I've used RL7 for light bullets and Varget for 68gr OTMs. The rest of my loading is with H335 and 55gr FMJBTs. Comparable powders include TAC and AA2230. I charge cases with a Lee Pro Auto Disk and ball powders like TAC, AA2230, and H335 meter very well with it.
When I started with .223, I was over-crimping. This flared the shoulder and caused jams, so, don't over-crimp.
I'm also paranoid about using "soft" primers like Federals in my AR, so I run CCI, either the standard SR, magnum SR, or #41 military.