Global West may simply not have tested their product with anything other than a standard ball joints. In such cases, it can be more of a CYA to not recommend a certain part. Not because of anything to do with it not working, but because it can open them up to some amount of liability.
You want the tall ball joints. Control arms can't do anything about the camber curve. They can only affect caster and by way of their design aid in more aggressive alignment settings. If you want the car to achieve higher levels of grip in cornering, you have to also correct the camber curve. The only way to do that outside of a tall spindle or tall ball joints is to relocate the upper control arm mounting points on the frame itself. On the F-Body, this is known as the Guldstrand Mod. It's not impossible to do on the A-Body frame, but the design of the upper mount makes it pretty difficult to achieve.
You're going to want the offset shafts. It will help you achieve a better alignment without a massive stack of alignment shims.
As far as spindle identification, it's unlikely you have some sort of tall spindle in there. You can identify a drum spindle from a disc spindle by the anchor bolt mounting boss. The drum spindle has a much larger boss than the disc spindle. Here's a good read on the spindles from Pozzi Racing.
https://pozziracing.com/brakes.htm#disc_brake_spindle
Since budget is a concern, I would stick with standard coil springs and put the savings towards your wheel and tire setup. The tires are easily the most important part of this whole equation and you have to get away from 15" wheels to open up your tire options.