Well, good luck with that. I think it's good going for that side chain comp, I guess you are doing a few passes through to compress every steam.
I like to take my productions to master in a proper studio I trust, they have pretty nice gear, the control room is really nice and they have many people working great there so you can pick the man depending on the style. Doing the mastering in the same place by the same person who did the mix is kind of anti mastering. Mastering usually correct errors in the monitoring and maybe a general decision mistaken by the mixing because you listen to it so many times or something. Once at the university we mix different tracks by different people in the same studio, a pretty good one, then we went to a mastering studio and all the mixes had the same problem at the low-mid range... I tend to do mixes a bit dark, easy to add a HF shelving in mastering and if I try to do them brighter I usually end up with other problems, so I just work my way and leave the mastering to bring up the HF a few dB. I could add that extra HF at the end but I don't see the point, a lot of added value with a proper mastering and it's usually quite cheap in a proper production compared to the complete production, I guess less than 20% in most cases, so, if I the client can pay that extra I think it really worth it.
JS