3mm needles. This is shetland wool either in stash or recycled from a failed Hoxbro kit (the latter, I think). I'm a loose knitter, and I'm getting about 27.5 sts/10cm , but the fabric feels fine to me so I'll stick with these needles and this tension.
Of course I'll vary the background and poppy colours, but for tension purposes I only need to knit with two colours. I think we'll go for corrugated ribbing, as shown (but on smaller needles).
All I need to do now is measure Chris and discuss things like length and armhole shaping and depth. He intends wearing this over a t-shirt so we don't have to go with loads of ease and baggy armholes. The swatch was knitted with floats woven in every 5th or sometimes 4th stitch, so I'll stick with this.
A close up