So to make sense of it all, so far the sleeves have been attached to the body of the shirt, complete with underarm gussets. I've been hand sewing this, backstitch for the seams and then flat felled using this nifty tutorial. I admit, the tutorial confused me a little the first time I tried it, but on the second sleeve I sailed through.
The other thing I discovered while making this shirt is that cotton thread is... rather annoying to work with. It knots at the slightest opportunity, and when working with something as delicate as cotton voile, you can't afford to be too rough. So I came up with the idea of tensioning the fabric while I sewed. This started out as stretching the section I was sewing over my first finger fingernail, but this was giving me quite a small area to work on, so I obtained a piece of leathr from a friend, and supporting this over that same finger, I had myself a much larger sewing area.
And so I finish off my post with a picture of the extremely rare, Well Behaved Sewing Supplies Support Suzie.