Please allow me to explain why you are having issues trying to use the "vase" printing mode...….
Firstly, lets settle a common confusion in terminology. Look at this shot of the part you're wanting to print. It' got the top cut off..:
Please humour me here.....what I'm about to say may sound slightly patronising...but it far from it. Promise!
Firstly, the surface the red arrows are pointing at is the OUTSIDE of the part...and also is the OUTSIDE of the shape being printed. Secondly, the surface that the blue arrows are pointing to is the INSIDE of the part....but is actually also the OUTSIDE of the shape being printed. And just for completeness, the black arrows point to the INSIDE of the shape being printed.
Why have I said this?? Well, "vase" printing is designed to extrude a perimeter along all of the OUTSIDE surfaces of the shape...in theory as a single path in the form of a spiral. In your model, the slicer ends up trying to create a path around the outside of the model...and then around the inside of the part...then around the outside...then the inside...and so on!. Essentially...…"vase" printing cannot work when there is an "internal" OUTSIDE surface...AKA a hole!
When you set the "Merge all outlines into a single solid object" flag is does exactly what is says...and fills in the hole. This leaves a single OUTSIDE surface....and the shape will happily print in "vase" mode.
I do hope my explanation helps you understand the ramifications of "vase" mode printing....and hence gives you an understanding of what can and cannot be printed using "vase" mode.
As far as changing the dimensions of the part....I very much doubt "vase" mode printing has any effect whatsoever.