Shouldn't be so hard for a guy to get a straight answer around here Duffer!
I'll try.
I've been wondering about my 8I's distance too since I've been coming up short with it a lot.
Went out on SA #1 and hit some 8i's from the fairway in no wind and high wind. Rapture Pro V2 rated at 140 yds, hitting Tour GI-S (same as Duffer's Tour GI-SD except one dot less Distance) Full Back Spin = FBS; No Spin = NS
All at 100% Power, all dinged or very close. Level ground, SA#1.
No head or down wind, FBS 130yd carry and 2yds roll on fairway
No difference in 136yd carry between 14 and 28mph downwind with FBS.
Ball rolled/bounced on fairway 4yds @ 14 and 6 to 8 yds at 28mph.
No head or down wind, NS 133yd carry and 8yds roll/bounce on fairway.
Slight difference in carry, 1 to3 yds more, @ 18 and 28 mph downwind with NS.
Ball rolled/bounced on fairway 15 to 20 yards with NS
Very little effect of tail wind on distance using No Spin, +3yds, with an increase of 28mph tailwind.
I agree with Duffer. That 8I performance is not realistic.
Shouldn't the ball fly farther than 3 yds more with a 28mph tailwind??