I'd love to be able to use jpegoptim or mozjpeg but the trouble is choosing the right quality level. As Steve Souders says in his comment on TFA, it's not possi

I'd love to be able to use jpegoptim or mozjpeg but the trouble is choosing the right quality level. As Steve Souders says in his comment on TFA, it's not possible to experiment with varying quality levels when you have hundreds of images to optimize. Because we haven't been able to solve that problem yet, we use JPEGmini, a proprietary (but not that expensive) vendor solution.