My thought would be to find an example of what you'd like them to look like and then determine how to get there. Can't hit a target you can't see, eh?
Concerning black on Padauk. Black or black-ish? In my mind black is going to hide color and accentuate grain pattern. In which case why Padauk? Ash or Oak might be a better bet. Best accomplished with paint of some ilk.
Black-ish would be more like looking through a black tinted lens and if I'm honest, making the red of Padauk turn black is not going to be easy.
Perhaps starting with something closer in color to what you want might be a better choice. Say Walnut or Wenge. On the other hand if you veneered in something light like Maple or Birch, it would be easier to accomplish the see-through black.
Coloring wood is a huge part of finishing. For a first spray project, I'd steer you towards something where you're not jumping in the deep end of the pool.