A 27"/630mm front wheel would bolt right in. The Weinmann 219 rim has a bit of a ridge in the middle, maybe enough to keep the pads from creeping inward. That stirrup looks pretty flexible.
Does anyone know whether stirrup brakes NEED that raised ridge down the middle to keep the brake pads out of the spokes?
I heard of some sort of pads with leather inserts which are supposed to work better in the rain on steel rims.