Looks nice, that's a pretty nice sized backhoe bucket!
I have a Brantly backhoe and the buckets are a lot shallower then yours.
I bet it's going to dig well!
How deep can that backhoe dig?
Depending on the size of steel lines you need, maybe look into larger brake lines for vehicles?
That's what I'm going to use fore my John Deere 140 Crawler conversion.