We make up two five gallon buckets at a time so we do not mix the dewormer in the water or the buckets until it has been portioned out in a smaller bucket. We feed the mash for a day or two to get the birds used to it if they had not had it lately. We do a big scoop spoonful of mash for two birds, put that in the smaller bucket. For a group of mature birds, count all the cocks and hens, each hen gets two and every cock gets three ml of either SG or Valbazen mixed into an amount of mash you guess they will eat in an hour or so. That also gives the birds down the pecking order a chance to eat.
So, I'm thinking you'd figure like 3CC per gallon of the Safeguard suspension, mix as thoroughly in water as possible, then mix into the mash? ( we have four peafowl and 38 chickens..some of the chickens are pretty young...6 or 7 weeks). I just don't see how you'd figure the proportions otherwise for a mixed flock of birds that are different sizes and ages, and they're moving around to different feeding stations, etc).