Re: GigaPulse (Orchestra) - Which recorded spaces?
GS3 Orchestra comes with GigaPulse Pro, which allows you to use GigaPulse impulses with ANY GigaStudio libraries (or with any audio you route into GS3 Orch if you have a GSIF-2 audio driver).
GS3 Orchestra and GS3 Ensemble come with GigaPulse SP, which is a restricted "player only" version of GigaPulse. The key point to understand is that GS3 Solo/Ensemble can ONLY playback GigaPulse impulses that have been embedded into GS3 libraries (effectively meaning the sample library has to have the impulses "built-in"). Realistically, there are very few GS3 libraries available with embedded impulses.
I am not aware of any list of GigaPulse Pro impulses, but there are 31 impulses. Besides the actual impulses, there is the ability to use different mics, and place those mics in different locations within a 2-dimensional space.