Probably not helpful, but I just came across this passage by Colin Rudder in Tested:
"... some people think it is worse for the instructor watching you stagger off all alone. I have never found this to be so even after authorising over two hundred first solos. They are either good enough to justify relaxing as they go or so bad you almost do not care any more."
Hmm ... quick look at my log book ... no, Colin didn't authorise my first solo, but he did authorise the second, third and fourth.