It's definitely a makeable shot and should be nice and smooth when you hit it. If it was being rejected, I would bet their table needs leveled or the wireform up there actually needs to be adjusted slightly.

I never have a reject (as in it hits something and comes back). The only shots that I have come out on my premium are if they just don't have enough speed which is usually me trying to back hand it.

Definitely a tough shot though!

So the best chance I've had of backhanding the shot into the death star is when the ball is rolling from the right of the game, and then flipping when it's almost at the very bottom of the flipper. I've done it successfully quite a bit, but it's no where near a sure thing, it's more of a I only have a couple seconds left, might as well try hail mary.

The ball can be coming from a dead bounce from the right flipper, coming from the right towards the left flipper (orbit, bounce etc) and even just be coming back down from the tip of the left flipper like if you were going to cradle it, but it hasn't stopped rolling yet. I have had virtually no success cradling it on the left flipper and then just flipping it into the deathstar with the ramp up. It will usually go up and not quite make it and then roll back down.

I have my game setup at 6.5-6.8 (I forget which). The bubble is between the lines like it is intended, but it's your game so put it wherever you want.

I don't have any issues with hard shots on my premium. Like I said before, nothing hits and rejects, the only ones that come back out are those that aren't hit hard enough. I'd guess the machine(s) you've played are too shallow if you're suspecting skipping or possibly the wireform in the back needs an adjustment (someone mentioned they had to adjust theirs on one of the other groups). Mine's been super smooth since I opened the box so I know it's possible to have ti smooth.