I disagree with both the tactics on your page, your one, and the one in the
tips section.
The best way, from my experience, is to hide behind a corner, step out, fire
a few nails, step back [well away from blast area of any rockets!]
You don't get hit, cos the response is too slow, the only thing that can go
wrong is if a good engineer is close by. In that case, lure him round the
corner - straight into a concussion greande [which you preprimed - of
course!] Then nail his ass to the wall!
Then get back to the task - get that gun!.
Changing class to kill a SG is pointless. If you cant kill one as a scout -
you should either learn how to, or not play scout!
Standing in line of sight of a gun, and nailing is equally pointless. A
rocket'll kill you outright, before you get the gun. An attentive engineer
will be stood behind the gun fixing it, wasting all your efforts.

Happy scouting,

[AnoD]Mephiston