We burdizzo all our male calves and they barely flinch. In fact, a lot of them
don't flinch. There's a lot of technique to it to get it right though - it's all too easy to not do a thorough job, but think that you have.
It takes a lot of physical strength, too. Thankfully BH has buckets of both technique and strength!
You can get the vet to castrate older lambs if managing entires would be tricky for you. I'm not sure what it would cost, but as with most things it's bound to be cheaper if you can take the ram lambs to the vet, rather than have the vet to the holding.