After much trial and error and many hours, here are the sliders that I've settled on that feel the most natural and give me a realistic gameplay experience against the CPU.
These settings are based on the Heisman base difficulty setting. They have been used by myself (obviously) and a number of others who agree that they produce an overall solid experience. Please try them out and let me know what you think.
Difficulty: Heisman
Offensive Skill: Heisman
Defensive Skill: Heisman
Quarter Length: 9-10 Minutes
Game Speed: Normal
Player Min Speed Threshold: 5
Home Field Advantage Effects: On
Ice the Kicker: On (user choice)
Penalties
Offsides: 70
False Start: 60
Holding: 50
Facemask: 50
Offensive PI: 55
Defensive PI: 55
KR/
PR Interference: 50
Clipping: 33
Intentional Grounding: 40
Roughing the Passer: 50
Roughing the Kicker: 15
Gameplay Settings (HUM/CPU)
QB Accuracy: 10/70
Pass Blocking: 25/65
WR Catching: 45/85
RB Ability: 35/60
Run Blocking: 5/95
Pass Coverage: 30/85
Interceptions: 35/50
Rush Defense: 30/100
Tackling: 35/100
FG Power: 50/50
FG Accuracy: 5/80
Punt Power: 55/60
Punt Accuracy: 20/100
Kickoff Power: 55/55