Well, I'm finally going to finish up my Adv. Nitrox & Deco Procedures course. I did the classroom & pool sessions once before about a year & a half ago. At that time I tried to go through the course in my recretional equipment & that proved to be completely NOT user friendly. I tried for almost 30 minutes to sling the stage bottle to my BC & never could do it (my instructor said he did have to give me credit for trying as long as I did). He then talked me into going to doubles. After a nearly disastorus first dive in them (got into a run away descent to 95ft in them), it has taken this long to finally start feeling comfortable in them (1-2/2 yrs & about 50 dives). In that time, a lot of what I had learned had become rather rusty & my buddy I started the course with has since gotten out of diving. We had the first class session last night. I was surprised how quickly everything started to come bak to me. We didn't get to go to the pool because of a scheduling conflict, but will be going in the next class in a couple of days. Hopefully, now I'll get this class finished up & do it without making too big a fool out of myself.
IMHO, a backplate and wing is the only way to go, I still have a soft back when I dive in the Carribean. Diving doubles definitely requires getting used to though. I dive my twin98's whenever we have a 2 dive charter just to keep my skills in tune. I also like to bring a full 3000 psi 80 cuft aluminum tank along. I have a transfer hose and can top off the twins for the second dive.