Curious---Tad left or right handed?

[RJNorton]

Here are the two samples I can think of regarding Tad's handwriting during the White House years. The first is an inscription Tad wrote to Robert on the back of a photo of Tad on a pony. The second is a telegram from Tad to Gus Gumpert. The web page here says that Tom Pendel wrote the first one. And if Ruth Painter Randall is correct on what Mary Lincoln said, then Tad didn't write the second one either.