I'm with mazdaspeed. Not possible with the original constraints. Lugged steel at those sizes can't hit the 23 lbs mark. Since size can't be compromised, and you're dealing with hills...
I'd search for a vintage Cannondale ST touring frame. It has the relaxed geometry, fit 32mm tires, lighter than steel, and stiffer at your size requirement. To further reach the weight goal, add a CF fork that would be appropriate for an ST frame. It should also aid in the ride characteristics.