You mount your reservoir wherever it fits in the case, there is no pre-determined spot. Depending on the height of the tube, you could probably mount it to that mesh grill at the rear of the case, If its too tall you might have to remove the fan above it.
Seems about right to me.
Dont know if its good, but I doubt its bad. But anyway, I recommend using distilled water over a pre-bottled coolant, theres no difference and its a lot cheaper and a lot more convenient if you ever run out while tinkering with your loop.