I am replacing a single tube hot water baseboard with a two tier unit unit in my kitchen. The supply comes from above on the right side and the return is on the left going down to the floor below. If I have a two tiered setup, should the supply be split to feed each tube simultaneously, or is it better to supply the top unit and then snake back to the lower tier? Setup is 3/4" pex and 3/4" copper fin tube element. I'm assuming if the supply is split then the flow to each tube would be reduced by half.