Donning the Yoke

Here we have my feeble attempts to design the yoke of my niece's sweater. Did I bother to figure out how many rows I need to cover in the yoke before doing this? No. Did I build decrease rows into all these patterns? No. Guess I was just too eager to whip out the colored pencils to be bothered with the technical stuff. Anyway, I'm going to synthesize these at some point soon (very soon... I only have about 10 days to finish this project!) into a workable pattern.

Here's the most viable candidate so far:



But I'm sure there's some part of the math I'm missing here. I didn't realize how spoiled I was by working mostly in Knitter's Almanac, which dissects each garmet archetype ("recipe") in detail before launching into the pattern instructions. The Opinionated Knitter contains the straight dope - EZ's newsletters - which don't dwell much on the details. Anyway, if anyone has good advice for designing Icelandic yokes, drop me a line (coughcoughHelloYarncough). I'm particularly concerned with getting correct math. The patterns in the EZ version are all 4-stitch repeats, but not all the decrease rows result in numbers divisible by 4, which puzzles me. (i.e., you start with 220 st then decrease to 147 stitches. What gives?). Also, from what I can figure out, there always needs to be a solid (non-colorwork) row in which to execute the decreases, correct? Are there general rules to follow when designing this type of yoke?

[X-posted at Fig and Plum]