I wound up just drilling out the screw. Whoever decided it was a good idea to use such a small screw for this application needs to get knocked out.
With the new springs on the bottom perch setting, my truck currently sits at approximately 41.5 inches (ground to center of fender) with a full tank of gas. This puts it 1/4" higher than mid-perch.
The ride is greatly improved over mid-perch. The "pogo" effect that many people encounter with the stock springs at that setting is largely gone with the new progressive springs. The ride quality is quite similar to the factory springs at bottom perch, but due to the new ones being progressive, they handle bumps in a much more dampened and controlled manner.
There is a bit more roll and dive than with stocks springs at mid-perch, but definitely not as pronounced as the truck had stock.
Overall, this was a very worthwhile upgrade. The stock springs at mid-perch to me always felt too stiff when compared with the rear. It gave the truck a bit of an unbalanced feeling. The progressive springs correct this issue, and the truck now feels properly sorted.
I would strongly recommend people NOT to do mid-perch and just install these progressive springs instead. They are the superior option by far.