That model isn't really suitable for printing in vase mode, so I wouldn't even try it. The author also writes 2 shells, so why not just do that instead?
To really see if vase mode is suitable for a model (other than experience), after slicing in vase mode, you need to inspect the preview in S3D carefully. Even if you have chosen vase mode, it may not be sliced in vase mode. Sometimes it is also necessary to tick the box "Merge all outlines into a single solid model" on the "Advanced" tab to get S3D to really do vase mode. When you do the preview, enable toolhead view and verify that it really is doing vase mode by "playing" the print.
This model is fine for vase mode. Turns out the issue was my extrusion width was set to 1.2mm to give the model a bit more strength. Once I lowered it to 1mm and upped the temp it came out fine. Vase mode cut 30hrs (yes 30hrs!) from the print time
Sure you can get it to print, but it doesn't truly print in vase mode. Large parts of it will, provided that you check the box I mentioned for merging outlines, but when it gets up to the part where the handles attach, the toolhead will jump across to the other side.
True vase mode is when the toolhead does all the printing with one continuous extrusion, and that requires the model to be suited for it. This model isn't.