Started out using my Harbor Freight plum bob and crayons to get some reference points.  Because the body is on jack stands and not 100% level, the measurements are slightly off from what the manual says.

Firewall bracket to floor and mark with Crayon:

Subframe mount under seat to floor and mark with Crayon:

A little off from what the book says…  Repeated five times to ensure the measurement was accurate.

Now start drilling spot welds from inside the car:

and from side bracket:

Start working from middle of car to outside of car using the seam buster (from earlier post) and pry bars to gently pry the bracket away from firewall:

I wasn’t sure if there were two columns of welds like the passenger side – there weren’t:

Bracket removed!

Floor and toe-boards to repair before putting new firewall brackets on and BEFORE replacing with the full floor pan: