In UpTick settings, you have the ability to turn on Currency Defaults and allow a CAD to USD conversion:
What this does is it takes the Default CAD to USD conversion (by default, the 0.74 which is what SH uses as well) and applies that decrement to your price. The default increment will also be applied as a function of a converted rate, (1% X 0.74), so when you go to your listings, they will automatically be priced if you save the above defaults at -26.74%. Note, you can always change your increment, but you need to be at least -26% to get the SH conversion rate, and whatever percentage you want to be below the market, you will need to multiply by 0.74.
So if you want to price in USD and be 10% below the market, it would be -26 + (-10X0.74) = -33.74%. We will push your price to the POS as a USD price, and then SH will mark it up from USD to CAN. You will not need to make an adjustment in Sync as SH makes the conversion. Once you save the settings, you will also see on CAN events an Est. CA price under the CMP in the criteria panel. This shows what the price should show on SH using a 1.35% markup for USD to CAN.