Pictures of your space? Scaled floor plan? We need to know what you are working with as it all needs to tie together.

IMO herringbone pattern looks best in large bathrooms and I prefer fewer grout lines on floors and shower walls Definately larger tiles if going this route

Do you think maybe a 12x24 tile? Just laid out...

"Do you think maybe a 12x24 tile?"

No, it is a minimum of 4x longer than the width.

If I chose the 12x24 I would not lay it herringbone.

12" x 24" would not lay out properly to a herring bone pattern. The tile needs to more than twice the width to get the proper proper pattern.

I would not be doing the 12x24 and laying it herringbone... I would lay it half-offset.

Well it’s just a completely different look. There’s nothing wrong with large format tile laid in an offset pattern, but it’s not herringbone. So it’s really just a design preference.
You may not be able to lay the 12x24 in a half offset. We have 12x24 in a couple other rooms and had to go with 1/3 offset to avoid lippage.