Printed vertically since I think the layerlines going around the model looks better than having it sliced along its length. I added support on the first layers manually, not for overhangs but for stability.
Vibrations
When printing the thinner part wobbles a bit when its half way done, so I reduced the print speed on the Prusa i3MK3S to 70%, later 60% to reduce the vibrations. I don't think it would tip over at 100% but the quality might suffer.
Layer Heigth
Since the Layers go “around” the model I don't think the 0.20 mm layer heigth looks bad. Sure, you can get improved detail with a lower heigth, but if you plan give it a layer of paint, most likely the paint will fill up the layer lines perfectly fine. The only place where you will see a difference is at the wide end and the engraved runes.