Sorry to be technical
but surely it depends on the relative viscosities of the jam and the clotted cream? Whichever is more viscous should be spread on first.
I usually have mine wit a pot of Earl Grey tea (brewed, not stewed) black, no sugar. So I will have to try out the suggestion of cider as an accompanying beverage.
(Technical icon as 'viscosities' is quite a big word for a Saturday.)
As for the correct way to pronounce "scone", if I ever meet the Queen, I'll ask her.