Beth -
The real question here is what accuracy do you need at the low end?
A scale with a max range of 15kg might only have a resolution of 5gr. That would be okay for measuring 10kg of couverture, but might not be okay for measuring some other ingredients you might add. So you would need to consider a separate scale for measuring small amounts.
An inexpensive digital "pocket" scales can measure up to a kilo at .1gr resolution for under $20 (but don't forget to order a calibration weight if you buy one of these). It's going to be cheaper to buy two scales than to get a scale that can weigh out 15kg with a resolution of .1gr. A 15kg scale with a resolution of 2gr can have a discounted cost of about ~US$160 before shipping. A 15kg scale with a resolution of .1gr will cost at least US$100 more.
While you don't need a washdown scale, there are scales in the ~$160 price range that are NSF rated.
I routinely use the Affordable Scales web site to locate scales for specific uses ... you could do this and then find a supplier in Canada if they don't ship.
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clay - http://www.thechocolatelife.com/clay/