Certain effects from wings are measurable in wind tunnels and on racetracks, though on racetracks it becomes a less precise measurement as the pilot is a much greater effect on the lap times mixed with 7,000 other elements. It's as much about "feel," as anything else. It's incremental improvements looking for small differentiating edge on competition. So this is interesting to me, not just applied to racetracks but to amateur enthusiasts like us. Looking at it from less quantitative more qualitative feeling & experience which IMHO counts very much. I was remembering a few things you all may share depending on how many years and how many different bikes you've ridden:
1970's dirt bikes
Wind pushes rider back and up, squinting as hard as possible wind in hair, 55MPH was unbearable for more than 5 mins.
1980's street bikes
Open helmets sitting upright are basically tiny hard parachutes that fill with air and pull you head off over 80MPH
2000's
Ducati Monster - forward riding position + huge gas take and head light creates small effective turbulent air bubble - 120MPH full face helmet crazy fun, stable enough, unbearable head bobble over 120MPH at the race track
2010's
Ducati SBKs: 848, 1098, 1198
OMG aerodynamics. 155MPH no problem, precise and wicked maneuverability, though >140MPH, wind is punishing on neck, baggy leathers, head bobble is troublesom unless in tight tuck. Knife edge handling on the 848 - wink to change lanes. Hard breaking from 120MPH to 20MPH is exhilarating at times nervous, a little flying by the seat of your pants feel on the track.
2020 PANIGALE V4S with wings + helmet AGV GP Pista R WITH WING: So far... Are you ....... kidding me? Where's this been? At 100MPH, I can drink tea with a pinky out. This champagne feel tipping into curves is easy like rolling over pillows. At 120MPH it's an arrow in clean air, and turbulence around other vehicles moving the same direction is recognizable, understandable & manageable. Hard breaking from 120MPH to 20MPH is stable fast and confident.
My personal conclusion: "The aerodynamic package" is a package that works. I would have to ride with and without wings to see what's the dif. Though I'm going to guess, there is a difference with exponential effects in certain situations. Right now that's enough for me to leave them on, I'll take it. It's not enough for me to think, "I'll just put them on at the track." Though to each his own. Would be interesting to do a feel test. I bet I could tell. Breaking hard I put my knees out and sit up, which is an extremely noticeable difference. At times wished I had one more thing to stick out. Well, here's that one more thing.