Presuming we'll spend most of our time on the tribars, their position in relation to the saddle is all that matters, it will be the same unslammed without spacers as slammed with them.
So you might as well have a slammed base bar with spacers. Lower base bar will reduce centre of gravity for cornering too.
So you might as well have a slammed base bar with spacers. Lower base bar will reduce centre of gravity for cornering too.