I’m just going to admit it - despite all of the reading, the second, third and fourth guessing, the white noise, the pink noise, 85dBFS, LFE level vs. other speakers, REW, calibration mics, matched speakers, test tones, SPL, -20dB files in Nuendo not playing at the same volume as the -20dB generator, reference levels, LU, LUFS, Dolby, Dolby, Dolby, etc, etc… I’m paranoid about mixing anything in here at all. I feel so close but yet so far. I guess maybe now is the time to hire a consultant to come in for a day or two and help me get it all sorted out properly. 
How about you just tell people what you want to work and deliver and then people can help you out?
In my opinion it doesn’t really have to be that difficult. It really depends on the use case.
Hey MattiasNYC… after writing that post I spent a few more hours getting clarity through research on the issues I had questions about - so I’m feeling better about knowing that I’ve got a procedure down for correct calibration. At this point anyway I feel like if there is an issue it can be corrected fairly easily. I’m just wanting to be sure I’m starting on solid ground before I devote hours and hours to a mix. And, it’s really the bass/LFO that I’m most concerned about. Because I’m mixing in a small room, bass and low frequencies are more difficult to tame. Room treatment and bass traps definitely have helped smooth out the standing wave issues and made the room more tonally flat over the spectrum. In truth, I’ve taken just about every step I can (including physically increasing the size of the room itself via construction) to set this room up as well as possible for the purpose. So now it’s just knowing that I can trust what I’m hearing, especially with LF levels.
In the past few weeks I’ve added a matched set of five new monitors and sub, which have taken my studio from a high-end surround consumer playback environment into a budget-conscious pro mix environment. Doing that has helped me to trust that I’m starting with a good foundation from an equipment standpoint - but in doing so I’m having to really learn the new monitors, which takes time. I think now I just need to practice mixing in here - a lot. See how the mixes translate to other bass-managed and non-bass managed systems, and see how the downmixes sound on different systems too. No room is perfect. However, whacking the obvious (and not so obvious) moles helps. And yes, people have helped out and it is always appreciated. My ultimate use case is to have a room I can do broadcast surround mixes in, and also prep mixes for completion in a film dubbing stage environment. My ultimate fear is making mistakes that would end up having the content be rejected, or finding out that the initial mixing I’ve done was not calibrated correctly, thus costing major time and money at the dubbing mix stage. Regarding the former I’ve delivered enough content for stereo broadcast that I’m pretty confident that won’t happen. The latter I’m just going to have to trust what I’ve done and live and learn.
Seems reasonable.
For broadcast I think an ‘easy’ way to check mixes is simply using consumer-grade alternate monitors. From built-in speakers to small Fostex or Auratones or what have you. The one thing I’ve found is that I consistently overestimate the loudness of music as an element in broadcast mixes for shows that are supposed to have music driving them. Specifically bass tends to overwhelm when the volume comes up in many rooms and at more reasonable listening levels music then feels less loud.
I’d also add that in my experience non-scripted programming like sports don’t really use the LFE all that much, and instead the playback system uses the sub for bass management. So for that sort of stuff I think there’s less worry about using the LFE channel inappropriately and facing QC rejection as a result. It all depends on the content you’re mixing of course.
For film just do what many recommend: Take a mix you’ve premixed and rent a stage yourself, even if it’s just half a day off-hours. Go in, play back, take notes, maybe try changes to make sure you know you can get it to where you wanted it to be, bring it back to your studio - reevaluate.