Which best settings for jpeg lossless ?

[Augusto]

Hello.
I want to use batch convert creating jpeg files.

About jpeg saving settings ....
What settings need to be used for create jpeg lossless format ?
What quality value for lossless and lossy having an good quality ?
For lossless "DCT" is slow and "subsampling" is default value ?

Enabling "Optimize Huffman table" not break the image quality ?

What feauture does "Use estimated quality (when possible) ?

Thanks for reply.
Have an nice week.