Broody jail doesn't have to be a small crate, I've used a 4x4 exercise pen before and it worked just fine (lots of pacing though, since there was room for it). So since you're dealing with 2 birds here, I'd toss one in the small crate and one in the big.I have a large dog crate I've used to separate them but it's too big for broody jail.
I have a bird that just got broken for the 3rd time this spring/summer. She's slow to break too, like 4-5 days each time. Pretty much as soon as she gets back into laying she'll start sliding right back into broodiness yet again.