
I have never used clamps, or tied off with floss. Any that a bitch doesn't deal with, I do exactly as already mentioned. Squeeze blood toward pup, and tear carefully, not pulling the side nearest pup.
Most bitches deal with this themselves, but, with it being a big bitch, you may find, if pups come too fast, she may need help. I've had a bitch be far too vigorous, and bite too short. I had to stem the blood flow with styptic. But the pup ended up with a hernia where she had been too rough.