Nobody has answered this so I'll just say what conditions my rhubarb thrives in. It grows in heavy moist clay soil at the bottom of a slope. (And has done for at least 18 years.) It is in shade from a tall row of houses until 11.00 am even at mid-summer. So I don't think rhubarb needs sun that much, in fact I think that long hours of hot sun would do it more harm than good.

Flora,
Thank you. I decided t put it in a protected southwest corner of the house. Primarily b/c I know I won't be disturbing that area for awhile. I needed to stick in some garlic (I know, wrong season), so I stuck it w/ the rhubarb and then discovered that they're good companion plants. So I'm hoping that this will be a good place for several years. Thanks again!

Not sure what is meant by 'good companion plants'. Since neither is much troubled by diseases or pests there isn't any protective effect to consider. And since rhubarb stays put for a decade at least and garlic needs to be planted annually in well cultivated ground I would have thought they were actually very poor companions. My two plants cover an area about 6 feet across and the leaves kill off anything growing beneath them. In my view rhubarb needs a dedicated space to itself and the garlic belongs in the vegetable garden.