On the first point, wrong. You cannot prove to anybody beforehand that you can do the job; the only way you can prove that you are capable is to get the job in the first place and then do it. What you need to do beforehand is show that you are well enough qualified to do what's asked, and the SNP are clearly best qualified for leading Scotland in the future.
On the second point, your entrenched view and avatar bring to mind images of old codgers saying things like "Computers will never catch on", "Whit, machines that will transport people in the sky? Never!", or "Horseless carriages that propel themselves? I don't believe it!"