JEDIT: Watching these scenes again, it might work to keep quite a bit of the footage. After the Vader scene, introduce Jabba’s palace with the Max Rebo band and follow it with Bounty for a Wookiee. It would be easy to cut around 3PO here, even keeping the thermal detonator bit. Then we’d establish all the characters as well as Chewie’s fate in the cell. Unfortunately 3PO is in the background of several shots in the failed escape scene, but it would be fairly straightforward to paint him out, I’d imagine. Surely no more difficult than removing timecodes from deleted scenes 😉 Anyway, with this done it would work to keep Han being thrown into the cell with Chewie, and then after Han asks ‘What’s going on, Pal?’ Chewie’s remarks could be interpreted to mean ‘Don’t worry, Luke will save us.’ It doesn’t have to mean that Luke was always part of the plan, merely that Luke is on standby if it failed. In any case, this would serve as a good segue into Luke.

Then we could cut from the cell to Luke working on the saber in the cave and the droid dialogue afterwards.

It does keep quite a lot from the theatrical film, but at least you could cut it down from there to your heart’s content. Since everything is already established, for example, the extended droid entrance to the palace could be cut down quite a bit. Maybe just have the wide shot of the droids headed to the palace, then cut straight to them descending the stairs to Jabba. That would save the dramatic door opening scene for Luke alone.