Looks like a good machine. Yeah, you want the gauge wheels to just contact the opener discs when they're in working position. They're not too hard to reshim if needed.
A couple things I forgot to to mention: check for broken/worn out bushings in the row unit parallel arms. The bushings in mine are okay, but the holes in the arms themselves are beginning to wear out. There isn't any side-to-side slop yet, but the row units do move fore and aft a little. I'm just going to run it this year, but next year I'm going to have replace the arms or figure out a way to rebuild them.
Check wheel bearings, too. I was fixing flats on both lift-assist wheels and found bad bearings in one. I'm surprised it made it through the 60 mile journey home from the auction site. I'm glad I caught it now, otherwise I'd probably have bigger troubles in the field.
Mine came with the factory liquid fertilizer setup, but the previous owner took the tanks and squeeze pumps off a long time ago. The manual has rate charts, but I don't know if it matches up with the John Blue pump you have. We've always used a hydraulic centrifugal pump for starter.
We apply starter in-furrow, and not more than 8gpa. We use low-salt formulations, too. I don't have any experience with 6-24-6, so I can't say how much to apply. I would think you could apply 10gpa with those coulters, though, as long as they're in a 2x2 setup.
Here's mine at the auction site:
We had to play with it as soon as we got it home: