Anyway. I have finally, maybe, found a foolproof way of making striped socks that do not a) have long floats along the sock axis or b) lots of ends to weave in, and c) also don't have weird-looking places along the axis of the stripe changes. The "sunset canyon" socks (my name for the red, purple, copper, etc. ones) ended up with a lot of shaggy on the inside, and one of them was definitely "holey" down the middle bottom for about an inch. I tried wrapping one yarn around the other at the point of change. I tried wrapping over, under, around twice, etc. But what I found worked (for me) was this.
A) Changing the yarn color *not* in the middle of the bottom, at the change in needles from 4 to 1, but several stitches "back" from the change. I had better control of tension when not at a "corner."
B) Making the change stitch with both yarns (a fat stitch) and then picking up the desired new color to go on with.
C) Repeating the "double" stitch every 2-3 rows for the width of the stripe, so the floats are very, very short, and making sure not to pull the floating yarn too snug.
The socks on which I'm doing this are mostly a two-yarn design, with only one brief appearance of a third color (souvenir yarn from making socks for a friend. One of the yarns is variegated; one is solid). My name for this pair is "tropical lagoon"--it's very sea-colored, turquoise (solid) and then shades of blue, aqua, and lavender.
More yarn came today...I need to spend some more time knitting, once I get this yarn packaged for storage. Uncharacteristically for this online source, it came loose in a box, not wrapped up at all. They've always sent yarn before in neat plastic, tightly taped. I'm glad this didn't arrive during a rainstorm!