Here is my 2 cents worth on the piece, and for what it is worth, I agree with you more than disagree.
While I lean towards Kralik on the piece, the shape, for what it is worth, strikes me as a little more of a Rindskopf shape. That being said, the ground color of the piece strikes me more as a Kralik color than as Rindskopf....especially in light of it's appearance to have a slight opalescent characteristic in the images as seen from the top. This may just be the images though, or a glow from uranium content in the sunlight.
The pontil mark on the piece is pretty nicely done. Although this is obviously not a solid indicator, many Rindskopf pieces have quite messy pontil marks.
The twisted rib decors such as this in the come in two variations, One is a variation with clean lines. the other version is in what I have referred to as a wavy line. I have only found wavy line examples by Kralik. In most of the examples of both of these decors, the following is an observation I have made on many piece. while not a hard indicator, it is something that seems to help point one way or the other if the shape is not definitively from one house or the other.
On Rindskopf pieces the lines in the decor twist from the bottom right to the upper left. This direction of rotation follows through on a great number of their decors that exhibit a twist. On Kralik pieces in the twisted decor which have straight lines the twist in the decor goes from lower left to upper right, or opposite of the Rindskopf twist.
On Kralik pieces with the wavy ribbed twist there are examples with the twist going in the direction of the Rindskopf straight ribbed pieces, but they are quite uncommon.
So, my gut leans me more towards Kralik than Rindskopf, but I still feel that finding the shape in another decor will provide the final answer. Attached images: First image is Rindskopf, Second is Kralik one of which is a Twisted Rib in the wavy line.
Last image is a Kralik shape, a marker for their production, in the wavy version with a twist opposite of most of their production.
I have not found an example of the decor on your piece produced by Rindskopf with the twist being in this direction.... but that does not mean one is not out there....
Craig