Sizing help.

A friend had a wee boy 3 weeks ago and is using cloth. I'd love to surprise her with some longies but don't have a clue of bub's measurements! He was 8lb 11 at birth so figured if I aim for something that would fit from 10-11lb mark? I've got joeli's longies pattern but not sure what sizes to go for. Any help from those who have knitted for newborns gratefully received!

I rarely sell anything smaller than my Small size which has 18" hips, 16" rise and 6" legs. They have been used from birth upwards so would probably be about right for your friend

Thanks heaps...will go for that