I’ve cut a LOT of 1/8" walnut with no issues whatsoever, I have not yet cut 1/4" so I don’t know the settings.
Give that thread a try and use the file / settings on the Walnut. Many times a test cut like that is needed. Thinking back, the only things I’ve cut at 1/4" is poplar and MDF. They both cut fine, but did get crispy a bit.