Yeah i quess you are right! I was hoping i could get away with some lighter tyres. I don't really like the fat anti punture layer... the 700x37 conti country plus is already 850 grams.
You might get away with them, but they have very thin side walls, and if a side wall goes or if you find you get a load of pinch flats it'll be an absolute pain in the arse. I don't think you will notice the weight that much once loaded.
I would go with some heavy duty touring tyres a la marathon plus or conti tour guard etc.