In my experience, the YFT are no deeper than 280 ft. There are usually YFT schools that stay deep (under the black fin) and random YFT's that patrol from 50 ft up to the surface.
If you can get a fast, slim jig through the BFT, then work it slowly at around 250 to 280ft (really depends on where they are marking), you can jig a YFT!
The YFT's that patrol from surface down to 50' you should try a live jig (similar to a tuna pen foil). Just make long cast like a popper, let it sink to a count of 10, then make a long rod sweep up and reel back down.