I got that top but started from the top. You should be able to snake your arm underneath the heat shield and just feel around.
Or use the same extension that you used to get to it from above.
Make sure your intake is pulled and it helps to have the battery out. From the driver's side of the engine bay just put your hand under the heat shield and feel for the hole. Make sure you have your engine cover off as well (I just assumed youve already done this, but maybe not a great cover).
Intake is still out. It just might be worth it to pull the battery here, I think? I can get my left hand around the heat shield and on to the stud. I can get my right hand through whatever hoses are on the right side of the engine and to the stud. "Problem" is, I don't think either hand is in a "tighten a nut" kind of ergonomic position there. My worry about using the socket is that I've got to keep it either pitched up or keep a finger on the nut. For pretty much all of the tough jobs on this I've been wondering why companies don't make more Magnetic sockets.