What do your mixes hit before loudness?

It doesn't really matter to be honest. So long as it's not so low that it's giving you a poor signal to noise ratio, and not so high that it's clipping or leaving no headroom for eq'ing then it's fine.
 
My mixes peak around -6...
But I engage FG:X pretty early and don't care anymore(funny thing is if I disable FG:X at the end my mixes still peak -6'ish)
 
I wouldn't worry tooooo much about numbers... as long as you leave some room. FWIW to the OP: your mixes are borderline offensively loud to my ears and they really don't need to be. Up to you of course.

If you are finding it difficult getting as loud as you want though - take a look at the sub lows. You may need to control them with a small shelf, filtering slightly higher or some multiband compression (or even a mix of those). Best way is obviously getting it right in the mix. I can use just the Massey limiter to get -10 rms without any fancy tricks. I'm even boosting some 60hz after my 2-buss compressor with a lot of mixes.
 
so far I'm finding the exact opposite in REALLY early testing.

I usually have a MIX RMS of around -18 to -24dB. With my old mastering chain I could easily get up to -9dB before it would start to get clippy. With Ozone 5, I can hit -7 to -8 and it still sounds "OK" by some standards. I'll render a master and then analyze everything and find it's REALLY loud with the same characeristics of a less loud ozone 4 master. If I bring it down to around -9 to -10 it's on par with the loudness I got with 4, but it sounds clearer. I'll do more testing today before I jump to 5 for sure, but so far I'm digging it.
 
Just got Ozone 5 yesterday. So far I like it and I'm mostly surprised how good the EQ sounds. Sounds very analog to me like Pro-Q. You can set the input volume in Ozone so you can experiment what works best for you. Personally I have it so that it's peaking close to -0.3dB coming in and also peaking -0.3dB coming out. RMS figures just change. :) Andy Sneap mentioned he aims for -10dB RMS loudness. Most popular releases are around -8dB though.
 
so far I'm finding the exact opposite in REALLY early testing.

I usually have a MIX RMS of around -18 to -24dB. With my old mastering chain I could easily get up to -9dB before it would start to get clippy. With Ozone 5, I can hit -7 to -8 and it still sounds "OK" by some standards. I'll render a master and then analyze everything and find it's REALLY loud with the same characeristics of a less loud ozone 4 master. If I bring it down to around -9 to -10 it's on par with the loudness I got with 4, but it sounds clearer. I'll do more testing today before I jump to 5 for sure, but so far I'm digging it.

What version of Ozone 5 do you have?