How Much Voltage Loss Should I Expect with 350 Feet of 12/2 Landscape Lighting Wire from a 200W Transformer?

I'm setting up some landscape lighting and am considering running both my deck lights (30W total) and path lights (50W total) either in series on one line or separately from the same transformer. The setup ideally needs to run about 350 feet from a 200W transformer. How much voltage or power loss can I expect if I daisy chain these lights together? I've heard mixed things; some sources suggest I should use 8-gauge wire, while a Home Depot employee mentioned a loss of only about 10%. Any advice would be greatly appreciated!