I'm beginning to wonder why Kordes' 'Westerland' hasn't been used much in breeding. I can say that my own experience demonstrates that it makes some very decent offspring, so maybe its just a style thing? It appears to be inclined to make large, climber-ish shrubs, and for the most part, large roses are not currently in vogue, so maybe that is part of it.
Anyway, lets look at this example. This is 'Westerland' X 'A Shropshire Lad', the latter being one of the more recent Austin roses, which, like 'Westerland' is a large shrub that can be trained as a "climber". (I put that in double quotes because, like so many similar modern shrubs of a certain stature, this rose is often referred to as a "climber" when in fact it is nothing at all like the true climbers: the Ramblers, Hybrid Multifloras and others bred from true climbing species. Of course, it can be argued that no rose is a climber in the true sense, as they have no tendrils or tools to grasp with. They are simply "opportunistic climbers", relying on chance that their prickles will latch onto something supporting as they grow towards the light.)
I saved this seedling at the last moment, only because it had such excellent foliage and a glimmer of pleasant color. I almost culled it because in the first two seasons the blooms were less full than I would have liked. This Spring, however, the blooms are reasonably full and quite attractive. (Certainly more petals than previously) It is showing excellent vigor as well, and appears to have excellent resistance to disease (so far). The fully expanded bloom shown here is about 4" in diameter. Larger canes are blooming in clusters of three to five, while laterals often have only one or two. Half open buds are yellow brushed heavily with flame, expanding to more of a "Peace yellow" with splashes of pink and red at the petal edges. Yes, it has a pleasant scent, though not intense. I'll be watching this one more closely now, I think ;-)
So, in case you were considering using 'Westerland' as a breeder, I would say yes, go ahead and see what it can do for you. It might not do exactly what you want, but I believe it is worth exploring.