To Fargle:
I personally think that it is a bad idea to go and grab scientists from Poland. In Valhalla, its understandable. We're going to blow it up/burn it down, so we might as well get some spoils while we're there. Plus, we are able to employ tactics that will disguise our involvement. However, if a group of Irishmen show up in Poland, then it won't be that hard to figure out that we had a hand in it. In addition, we don't even know where the scientists would be, or even if they would have anything useful to contribute. Poland's tech level is most likely way behind ours.
As for the German science co-op idea, go for it. Anything that will strengthen our standing with our allies/vassals while boosting our research is a good thing.