The Episode V script suggests that Yoda had Luke stand on his hands on Dagobah as a training technique:
Luke's face is upside-down and showing enormous strain. He stands on
his hands, with Yoda perched on his feet. Opposite Luke and Yoda are
two rocks the size of bowling balls. Luke stares at the rocks and
concentrates. One of the rocks lifts from the ground and floats up to
rest on the other.
Yoda: Use the Force. Yes...
Yoda taps Luke's leg. Quickly, Luke lifts one hand from the ground.
His body wavers, but he maintains his balance. Artoo, standing nearby,
is whistling and beeping frantically.
Yoda: Now... the stone. Feel it.
Luke concentrates on trying to lift the top rock. It rises a few feet,
shaking under the strain. But, distracted by Artoo's frantic beeping,
Luke loses his balance and finally collapses. Yoda jumps clear.
By standing on his hands, Luke is forced to concentrate both on maintaining his balance and lifting the rocks with the Force. Obi-Wan was likely having Quinlan Vos do the same.
The script makes no indication that Luke had an enhanced connection with the Force later when he saw the Cloud City vision -- that scene seems to be to convey Luke's increased skill compared to the earlier scene. It's actually Yoda's mention of "old friends" that disturbs Luke with thoughts of Han and Leia in Cloud City:
In the clearing behind Yoda's house, Luke again stands upside-down, but
his face shows less strain and more concentration than before. Yoda
sits on the ground below the young warrior. On the other side of the
clearing, two equipment cases slowly rise into the air. Nearby Artoo
watches, humming to himself, when suddenly he, too, rises into the air.
His little legs kick desperately and his head turns frantically,
looking for help.
Yoda: Concentrate... feel the Force flow. Yes. Good. Calm, yes. Through the Force, things you will see. Other places. The future... the past. Old friends long gone.
Luke suddenly becomes distressed.
Luke: Han! Leia!
Similarly, the script gives no indication that Luke's connection to the Force was improved by his position in the wampa's cave:
The jagged face of a huge ice wall sits gloomily in the dim twilight of
a Hoth day. Luke hangs upside down, ankles frozen into icy
stalactites, his extended arms within a foot of the snow floor. One
side of his face is covered in a dried mask of frozen blood. He opens
his eyes as a chilling moan of the hideous ice creature echoes off the
gorge walls. Luke pulls himself up, grabs hold of his ankles, and
futilely tries to unfasten the throngs.
Exhausted, he drops back into his hanging position. As he hangs there,
he spies his lightsaber lying near a pile of his discarded gear, about
three feet out of reach.
He focuses on the saber and, as his hand strains toward the weapon, he
squeezes his eyes tight in concentration.
Just as the ice creature looms over Luke, the lightsaber jumps into
Luke was hanging upside down in the wampa cave simply because the wampa put him there, and he succeeded in grabbing his lightsaber at that time because he had just regained consciousness.