The sight-size method involves setting up sitter and canvas alongside each other under high natural light, as seen here, and taking measurements from a distance. This was done during our first sittings
The commissioned portrait is important in the tone it sets. As a portrait painter you are aware of how much weight a gesture can carry. Moving a single finger can force a look of relaxed comfort or tension. The slope of shoulders tells much of the balance of thought, and of course there is clothing, background, size and scale to be worked out, too.