oh tricky Kuka. Anymore than six or seven stitches and stranding is no good so you're about right for that. I don't think you have to worry about the colours showing through. It's very dense fabric and the blue doesn't show through the grey on my jacket.I think you should be ok.
I think I'd go with weaving in too... looking forward to seeing pics! :)
Weaving would be my choice, particularly with something not 100% wool.
Hi Kuka,I recently knitted this Owl http://www.flickr.com/photos/72298084@N00/445483639/in/set-72157600046177589/I tried nearly every method for the eyes, and settled on intarsia-which is what the book said to do. I wound little bits of wool and joined in a colour for each section. I tried stranding, but it just looked not nice on the front stitches.
Thanks for taking the time to leave a comment! Have a nice day =)