Gemstones are not grade like diamonds. The clarity gradings assigned to those rubies are assigned by the vendor. They mean little and cannot be compared vendor to vendor. With that in mind can you post the links of the stones you're referring to?
I agree with the clarity comment already mentioned
May i suggest some paper jewelling? Draw a paper mock up of the stones measuring and cutting them as acurate as possible. And see how you are happy with the size/shape on your finger. Sounds silly I know. But I've found it helpful in the past.
Depends on the colour of the two stones, the cut of the two stones and a whole heap of other variables, so in short I can't tell unless I see pics of the actual stones. Sometimes for you size might win. For me colour always wins.
I'd go for the colour and how nicely the stone glows and sparkles. There are many ring designs, especially those with halos and split shank, that help to give the appearance of more finger coverage.