Nice one Bob. I was one of those two trainees. Those of you who manage to attend the presentation evenings will know how knowledgable and passionate Steve is. I thought before the course how is this going to take 4 days, and at the end I still wanted more time on all the "extras" such as multiple stage rigging etc.
I've just finished my tec45 this weekend, so went back to a STD twinset, albeit with 12kg's on it. Still really liked diving it, but as I was hauling it back up the steps and hill at St Johns point, or doing a gas shutdown drill, the case for side mount became very strong.
Apart from this the biggest benefit is the ability to easily stay in trim in any body orientation. Not easy in a heavy twinset, especially if you have no air in the wing.
Re practicality, after learning entries and exits from Steve, I'd rather dive side mount. Even in a heavy sea on a boat I'd rather kit up in a side mount rig than try to balance my twinset and stages.
Now the only question is when to make the switch. Def going razor as part of the course custom fits it and you get all your measurements.
Big thanks to Steve and Greg, my fellow convert. Also to Declan (Diving Dec) for tec 45 this weekend.