Lots of folks do different things. All I can tell you is how we do it here.
We feed 1 cup of Purina Goat Chow, a scoop of alfalfa pellets, free choice grass hay and loose goat minerals to everyone. Bred does, approx. 100 days prior to kidding date, has their grain VERY gradually increased until they are getting 5 cups of Goat Chow a day divided into 2 feedings. 30 days prior to kidding, they get CD/T and BoSe shots. Basically, that's all we do. Hoof trimming and deworming is done the day they are bred. I don't like to trim hooves when they are pregnant as it seems to put too much pressure on those bellies.
Do you give the CD/T at 30 days prior regardless of when they were last vaccinated? I'm guessing it would make sense to do so since it's the kids that are really benefitting.
Just about everything I've read suggests revaccinating bred does with C/D-T "about three weeks" before kidding so the antibodies can be passed along to the kids through the colostrum. I'd call 30 days "about three weeks"...and, yeah, it's done pretty much regardless of the last vaccination date.
I try to time it so that the does who kidded in January last year, will kid in January the next year, so that they're getting revaccinated 'on time'...
With first fresheners, if they were born in Oct. but don't kid until January....they get a booster in September AND again 4 wks before kidding...the first one to keep them UTD, the second for the babies / passive immunity.
I do the 1st Bo Se shot when I give them the CDT booster, the 2nd Bo Se is given 2 weeks later.