Then why confuse the issue by bringing the trainer into your post?
I routinely ride 40-60 minutes into at 10-20mph headwind, using big chainring. It is great training for long climbs even though those are often 34 chainring and 32 cassette (or one/two steps above it on 11-32 cassette). The big difference? On climbs the sweat rolls down my face, into my glasses, and onto my bike. That doesn’t happen riding into a head wind. Not joking, I’m being completely serious.