As per my vet, I always double the dose of ANY dewormer, due to the higher metabolism of a goat. I've used Ivermectin with very good results, but mine is a different herd, in a different country. Resistence is always an issue, so it wouldn't hurt to do fecals on your own goats after deworming to make sure the product you've chosen is effective.
For me, if want to be absolutely certain the goats are dewormed effectively, I use the Ivomec injectable, but that stuff stings like crazy and in my mind borders on goat torture so I only use it if I have a new animal with a very serious worm burden.
My old vet gave the injectable to my horses orally so I asked about the carrier burning the esophagus and was told it is fine.
I'm sure you probably know this, but be warned about Valbazen. Don't use it on pregnant animals, especially in the first trimester. As long as I'm certain there's no chance of pregnancy, Valbazen is my wormer of choice, as it takes care of tape worms. Ivomec and that family of wormers does not.