For Tecumseh HM100 159287P - seeking info to connect magneto shutoff

On the top of the ignition coil (under the pull starter), they'll be a small tab.
 
Your kill wire pushes onto that and to where you currently have it attached under that spring loaded
part.  That shorts out the coil killing spark when activated.
 
I don't know what those extra tabs are for... I'd tape em up un-less they go somewhere specific
for another / separate safety kill switch ..