OK, I am registered for The Firm too. It will be great to gather and run with Bullittheads!
What I have learned from running multiple tracks is researching the track. Print out a copy of the track map. Downsize and tape it to your steering wheel hub. Visualize the turns and learn their numbers. Look at the Google satellite view. See where the dark lane lines are. They are a hint to the safe track line. It looks like turn 8 is the only sweeper, with early apex, track out, turn in and then a late apex. Otherwise, Mustangs perform best with late turn in, late apex and wide track out with the other turns.
You Tube is good but only view similar cars. Mustangs! Rear drive solid axle. Not first timers. I found a great video of a Mustang line-"The Firm Track", "Track Attack at the Firm 11-19-16" by Matt M. He uses all of the track, curb to curb, with late turn in's, late apexes and nice track outs. Smooth is fast. Watch this video every night before bedtime.
If you watch the Spectro Racing videos, those guys are time trialing amongst each other. Beware of their lines and technique. They are using horsepower on the straights and not smoothness on the curves. Minimal use of turn in, apex and track outs.
When we are learning a track, we progress, letting our butt meter control our feet and hands. Once the track is learned, the envelope limits are pushed. In rain, keep off the brakes, and be even more gentle on the throttle!
We are not racing, just gentleman enjoying our BULLITTS at speed. Smooth is fast!
PS- DO NOT watch the line of the car in front of you.