Here I do the does at 4 months of pregnancy...and usually do the yearly in Jan/Feb so I plan breedings around that(and the weather too) Kids I have given 1st dose at 4 weeks and the second one at 7 weeks but , now that I know more I plan on doing kids at 5 and 8 weeks....as far as wethers bound for the freezer thats up to you...do you want to give them the protection til they get there or not ...meat withdrawal is like a month after you inject it.
Here, it's Covexin 8 at 8 wks and 16 wks. Does get it annually at 4 months gestation (sometimes twice a year if someone didn't settle at first or something and had to be re-bred). All the bucks get it in the spring. I also usually give a 2cc booster when I sell an adult because a long time LaMancha breeder told me that the risk of entero is higher when changing homes/feeds/climates....Fortunately, I've not had to deal with it yet but it's one of those things I will go to GREAT lengths to avoid.
After a few years, I switched from Covexin 8 for a while because the vet said I would get fewer abcess reactions at the injection site with the OTC stuff. Bar Vac - I think. I still had reactions and felt I was getting less protection so I went back to Covexin 8.