I raw feed too, it's been over 13 years now. Dogs, cats and ferrets, they all do great. My latest dog to be raw fed is a Great Dane, I started from the day I brought her home and she transitioned wonderfully. Home cooking is possible but I know very little about it and from what I gather it requires more effort on your part to get it all right. For raw feeding there are different ways, but I follow prey model raw. Meat, bones and organs. Some people do veggies too, but I stopped that within the first year of switching to raw. The only thing I supplement with is fish oil.
No GSD right now, though I had one named Nevada. She passed a few years ago. Now I have a Great Dane named Freyja and maybe a GSD in the near future.