Well that is something for you to try Bodgetandscarper, I must admit it is a bit of a fiddle getting the plating yarn in its correct place, so not something you want to be doing when you are tired or it is dark, but the results are very pleasing.
Now when I knitted my plated boucle sweater, all of this was industrial yarns, and each on its own cone and some of those cones were in fact huge. Well the whole sweater had been knitted and sewn up - well the side seams and sleeve seams had been sewn on the sewing machine with a narrow zigzag, the shoulder seams are never cast off as such, they are either grafted or the stitches put back on the machine i.e. both the back and the front pieces and one loose row knitted and then cast off, and the neckband was again all held stitches and put back on to the machine when the neckband had been knitted and then one loose row and cast off. Well my sweater was just laying there and I looked at it, looked again and though why does that look a different shade of blue, moved the sweater in case of shadow and it was still there, and yes it was very noticeable when laying out flat. So what did I do, start taking it apart - not easy by any means, as I have said I have open stitches on the shoulder seams, and around the neck, and machine zigzag side seams. I carefully put some markers in where the colour changed - this was the font only and a good way up the front but before the armhole shaping. Having carefully threaded all shoulder and back neck stitches onto a nylon cord I then proceed to undo the front, but as it was plated this meant doing this very carefully and winding each yarn into a separate ball. I carefully pulled it back to my marker, and rehung the stitches back onto the machine, then checking that I had the right shade of boucle, threaded up again, rethreaded the plating yarn and reknitted the front without dropping a stitch and then finished it all off again and you would have never known. Yes it was a fiddle, but well worth doing.
Unbeknown to me when the boucle yarn was spun on to a cone there must have been a break and a new end was knotted on and it was this that caused the problem, it must have had more than one join as all the rest of the sweater was the same shade, all but from the middle of the front only. I suppose that is the gamble we took then using these lovely fine industrial yarns.
If you are going to try plating, I hope you have a double ended bodkin the one you use for transferring stitches from the ribber to main bed, and then there is the tiniest gap in the yarn feeder right at the back on the main carriage. As I said I reversed my plating for the welt parts as I wanted the stocking stitch hem, plain side, to contrast with the boucle which was the purl side, so it meant I had to keep changing the yarns over but so well worth it.
Have fun and enjoy playing.