Spinning space-dyed roving leads to many possibilities -- how will the colors "play" with one another when you ply? Will they be muddy? Will the lovely red and purple turn into some sort of mauve from a distance? How can you control this?
I prefer my knitting yarns to be 3 plies, and I usually Navajo ply, but lately I don't usually try to keep the 3 strands in the Navajo the same -- usually I try to fade in/ fade out if the color changes are long enough -- a Navajo loop that's AAB, then a loop that's BBB then a loop that's BCC (or, ABB, BBB, BBC ... or, AAB, BBB, BBC ... you get the idea ...) this gives some heathering around the color changes.
Actually, I started Navajo plying this way (mixing colors) because of a two-ply I once did: split a space-dyed roving in half, spin half onto one bobbin and half onto another. Then ply the two together. It came surprisingly close to matching up, and the color runs didn't get so far off track, that the color changes stayed together, with ... a little bit of heathering around the changes! I liked the look, so I brought it into my Navajo plying. The picture shows the experiment -- the left glove is "perfectly" Navajo plied, and the right glove is a 2-ply with the colors almost matching up at the edges. Aaaaah. (This fiber was from a Totally Tubular Spinning Kit with the Fingerling Gloves.)
So, there are two options for you ;-) sample, experiment, see what you like...
(this is based on a post by me to sockamaniacspindlespinners, 24apr07)
(the roving at the top is Baabette's Fleece, a locally dyed fiber I bring to shows but have not yet put up on the web site ... see it in person at The Bellwether's booth at NwRSA in C'our d'Alene ID and at Black Sheep Gathering in Eugene OR!)