I have nevr tried the barrel knot either.
Like I said I have come off the bend, but the majority of the time I do also come off the eye. You get more chances of fish taking BOTH flies.
Mostly, I tie a long piece of tippet to my leader using a SURGEONS KNOT (two wraps) and leave the tag around 4" to 6" and tie the first fly on that, the dropper on the long end.
Or, I will put a long piece of tippet on a short leader. Slide the first fly up to about a foot or more from the connection and make a Surgeon's Loop and attach that fly. the end one on the end with a surgeon's loop. Both flies can move. Plus when stripping I think they act more natural, then one with the weight of a fly on the bend of the hook.