Grafting is, I think, a revenge exacted by forces mysterious for knitting sins unknown. How else could the perspiration, the lip-biting, the mortal dread be explained?
I don't think there's any way around it this time. Look:

It would be a nice touch to have the waves flow down from the shoulders on either side. Since the halves are worked from the outer edge in, the only other way to join them would be three-needle bindoff, which would be bulky and obvious. Grafting should produce a flat, seamless fabric, if I do it correctly, and get my tension right, and don't pull out my hair in fistfuls or commit seppuku on a DPN.
On a happier note, I think I've found the solution to my edging woes. How about a variant on this, worked as an edging around a YO row or two? It would create a straight frame for the center panel, without peaks or points. I think it might look quite modern...
Steph - these photos show you what I did to dye seperate colors:



Basically, I tied off sections I wanted colored, and just dyed them in seperate pots of color. It's not any harder or more time-consuming than doing a single color, really, especially if you use a method like Diana's with mason jars in one pot - that way, you can do them all at once instead of having to wait between dyes. It could be a fun project with your son, mixing and combining colors.
Eek - I'm not sure what colors I used, exactly. My documentation for this project was really shoddy...I think it was something like
Blue - 3 packets Berry Blue, 1 packet Lemonade, sprinkle Grape
Sand - 3 or 4 packets Lemonade, sprinkle Black Cherry, sprinkle Berry Blue, sprinkle Lemon Lime
Orange - 1 packet Orange, 1 packet Black Cherry, 1 or 2 packets Lemonade. Half this solution was poured out to reduce the saturation of the color.
My regular grocery store is attached to the shopping center of a retirement community - I must say, their Kool-Aid section was woefully lacking. Where were my X-Treme FlavR Twistz? Where were my Kool Aid Tinglers? Clearly, our senior citizens are missing out on all the fun.