Drinking from a firehose

When you're alternating colors each row the carry is so short its pretty much just like watching your tension normally, there's no problem there at all. there are many books, etc. that suggest doing alternate rows from two skeins of the same color if you're worried about slight color variations, or to break up pooling in random multicolor yarns.

You do have to pay attention to the tension when carrying colors up a couple-three rows, but I've done it quite successfully.