I should take a ruler and mark lines, lol.

At first sight, it looks like they have the same lenght.
Yet.. I don't know how to say the word in English! The crotch girl. Spencer farther from the floor than Jon.
Spencer's legs are much longer. Even if he wears the jeans with the waist below where it should be not to make Jon feel bad :P

But as someone said here, no matter how much taller Spencer is. Jon tops.