Roving, like yarn, is never a promise of what a thing may become. How I see it, how I work it, and how it unfolds under care of my hands could be world’s apart from what someone else would do with the same medium. I like to think of it as birth because the possible combinations appear reasonably infinite.
Take this lovely roving I oggled and ordered from Knit Witch:

Commercial rovings were intimidating to me at first. I wasn’t confident my spinning techniques were “worthy” or anything other than the alpaca roving I labored over. I was wrong. The luxury (so to speak) of having things combed and ready for your artistry was almost easier than fussing from beginning to end. I digress.
First things first, take the label off the braid and unwind to get a good look at all your fleece has to offer. Note: not all ready-to-spin fibers come “braided” like this. Combed top, slivers, and batts all look different. More on that as my addiction unfolds. In principle, I would say the plan of attack should be the same.

The braid is basically one long run of prepared fibers looped up on each other in a pretty way to keep them together and neat. At least this is my interpretation. I deconstruct the pretty and look at the whole pile.
I knew I wanted to do a two ply so I imagined the best way I could divvy up the fleece over two bobbins. To this end, I laid out the sliver/top (still not sure which is which) and tried to match color repeats. It is SO long there is no way I would predraft the whole length of it so I knew I was going to be tearing it into manageable lengths. This exercise helps me decide where to make the tear. 
For this fiber, I divided the whole into thirds, which gave me a blue/silver/teal repeat I could wrap my head around. Each of the three got divided into quarters and I predrafted and wound into loose clouds from the same end for each of the four. I kept the same quarters together. When I was done I had a basket that could be translated into text thusly:
Four balls of blue/silver/teal/silver/blue/silver/teal (you get my drift), four balls of the next chunks of color and four balls of the third. In this way, I could figure on nearly correct color alignment if I took one ball from pile #1, next ball from pile #2, next from pile #3, back to pile#1, #2, #3. Stop, End of bobbin. Then I had two of each left for the second bobbin.

I figured my reasoning was sound. The only complication I considered as I spun is what anyone who braids knows – sometimes the ones that have more overlap are shorter. If I pulled a little less on one of the balls and a little more on the next bobbin the whole thing could be thrown off. But it was as close as I was gonna get.
The next step is to have the Chief Inspector make sure your bobbins full of singles pass his high standards. Then ply.

Not too shabby in the match-up department…..
There it is, all 100-and-lost-count-on-the-niddy-noddy yards of squishy two ply.