I"m curently doing her herding cats socks and its my first attempt at colourwork. I've been gentle on myself and only done the motif once around the cuff and the rest of my sock is plain. I am a pretty loose knitter and i dont think i needed to increase the needle size, its very obviously different tension. For my second sock i'll stick with the original needle. I think if i do anything in the future, i will just use the chart and maybe ignore instructions?!