After trying to hop a vulture over the outside mineral lines on outsider and failing thrice I decided to look into how to get vultures over the mineral line. I tried several methods and the one below worked 100% of the time.
Get the (1)vulture in place and hotkey it. Put it in the smallest niche in the line. You can get it close to the (3)key patch by right clicking it while having the vulture selected.
Select your (2)SCV and have it mine from the (3)patch.
Select your (1)vulture (hotkey) and right-click the (4)area behind the patch once, then right-click the (3)mineral patch once and then spam right-click the (4)area.
Hope this helps, cheers
I realise I haven't tried this with Dragoons as well but I'd reckon the same method would work.