"Filling large grooves is easier with a higher WFS, but excessive WFS for the welded thickness can lead to burn-through."
Excess wire feed speed will not necessarily cause burn-thru. You can tell when you have excess wire feed speed when you start feeling the wire bump in to the metal you're welding. You're more likely to burn through if you don't have fast enough wire feed. Just my experience talking here.
My MIG machine has 4 power settings and variable wire feed speed. Each one needs to be adjusted for each specific welding job.
