Ok, no experience wreck diving but here's what I've found:
With a goodman handle on the light, the std reel is almost impossible reel in line unless you want your light beam going all over the place as you reel it in (looks very much like a buddy in serious trouble). I usually just clip off my light but then of course it's not pointing where I want it.
With the sidewinder reels, laying line with the reel in the same hand is simple. Reeling it in is also simple except the wrist motion required to move the reel side-to-side so the line lays easily tires out my wrist quickly.
Now, if you ditch the goodman handle on your light head, the std reel works very well and you hold the light head between your palm and the reel's handle. What would be nice is a easy snap on/off goodman handle so you could use the light without it when doing reel work and then easily reattach it when you're not running the reel (95% of the time in cave diving, probably much less in wreck).