There's a whole thread on this very topic, with pictures.
http://www.scubaboard.com/forums/sidemount-diving/447292-do-you-dive-side-mount-side-slung.html
Well things that look and work great for some types of diving suck at others.
My wife used my Razor in MX so I used my Hollis SMS100 with AL80s and it was way overbuilt and over complicated for the task. Likewise on my hips its impossible to get hp100s above the lower plane of my body with a Razor.
I would find an instructor who actually willing to help you with gear issues. The "personal preference line" sounds great, but here you are unable to even demo expensive rigs you are contemplating buying and having to turn to the internet for gear instruction. I feel its a cop-out to proper mentoring.