Craig, how high is the ceiling/floor from the first floor which you are trying to heat? Are the second floor rooms walled off or is there cathedral ceilings allowing air movement? You say the first floor is radiant, you may not have to heat the second floor, or just install some hot water base board or radiator. There are some nice new radiators on the markets now or find and old cast iron one. The heat load on the second floor would be far less than the first floor.
I am under the impression that you need at least a reflective air space, or insulation of some substance to keep the heat in the direction desired. I don't see any reflective or insulative material in the second version. Warm board is wicked expensive.
