I too need a pair of knobs for an Aria Pro II Elite bass
I am doing a 3D model, but I have no measures of the original knobs, so if anyone can measure the dimensions I can adapt them into my model.
I made a little screencast :
It's made in the free software blender :
I since made a shorter version, let me know if you want a copy of the 3d model file
The teardrop switchknob or one very similar is around on eBay, if needed:
And if you have an old bass in the need of a fresh-over or upgrade I found this guy in finland
Best regards, Brock