Quote:

. And despite comments to the contrary, we found there was a significant time savings on the portages by single portaging

I think that's true IF your portaging as you described and not straining then recovering because you've bitten off more than you can chew. ;)
Another thing to consider is that tripping in a group gives you a "margin' of error that a solo paddler can't afford.
IMHO no matter how you do it, being safe and avoiding injury should trump all other considerations.