I would go with a maximum of 1/8" width. With a stylized tile such as a wood grain, the last thing you want to do is take away from the look of the floor and anything larger than an 1/8" is going to throw your eye off on the color and look.
Check your manufacturer specifications, most will have a recommendation. All tiles are not created equal; most tiles vary by 1/16", some by as much as 1/8". When you plan for a 1/8" grout joint and have a tile variance of 1/16", that’s half of your joint and it will be noticeable and look sloppy. Even worse would be the 1/8" joint with a 1/8" variance in tile size, where does your grout joint go then? NONEXISTENT. Most of my guys would be hesitant to consider a very small joint in a large space. I would expect the manufacturer to recommend 3/16". That is the standard size for anything over 12x12 in the Pacific Northwest.
1/8th or 3/8
You can go with either a 1/16” or 1/8” grout joint depending on the quality of tile and the manufacture’s suggested grout joint.
1/8 to 1/16 as your preference