I would go with the diamond edition just for the extra flexibility on the mic positions, DIVISI, and the fact that $400 really isn’t that much for a nice sounding library these days. HOWEVER, the bigger the library, generally the more resource intense it is. I bought a newer library and it absolutely crushed by old computer. If you have an older computer and not much ram this must be taken into consideration and I would probably go with the gold edition in such a case. Solid State drives and ram make a world of difference.
24 vs 16 bit is nearly meaningless to me. Each sample in the wav (or whatever sound format) has an extra byte of accuracy, so instead of having a value between -32767 and 32767 (2^16/2) a given sample has a value between -8388608 and 8388608 (2^24/2) .Everything gets divided by the max value and up-sampled to 32-bit floats (or doubles) in the audio engine for processing either way - I don’t think there’s any real difference in sound quality. An extra byte can be better when it comes to processing, recording, effects, and will give you more headroom, but the difference is negligible. However, 24 bits WILL take up much more memory.