SGA canon question?

Okay, make that two questions:

1.) I seem to remember Sheppard started calling Radek by his first name when they were face to face after a while, maybe in the third season or so. Is that right, or am I making this up?

2.) What does Radek call Sheppard? Sheppard, John, or Colonel?

(...Yes, I'm writing a short John/Radek fic, possibly. The sg_kink meme prompt was too good to resist!)