Evaluating Classical Music Albums

1. By and large Studio is to be preferred over Live.  

2. There are many orchestral recordings in 60s that are great.  This was a time of great optimism in Europe and it comes out in the playing.  This typically means that you have to go for LP.

3. The popular orchestras and popular conductors are generally safe bets.  The trick is the smaller labels / artists.  A striking example is Sibelius Violin Concerto performed by Dylana Jenson with Ormandy conducting the Philadelphia Orchestra.  (LP version only, I'm afraid).  Another is the Punkt Label that put out Haydn Symphonies.  Just too many to mention.

4.  Hi-Rez (not more that 96Khz) is often good.

5. Be aware of reissues.  For example the Sibelius mentioned is disappointing on CD.  Likewise the other way round - new music 'remastered' for vinyl.  

Not all that helpful sorry but I think you know it is a thorny issue.

Most orchestral releases are from concerts, due to the lack of funds for studio recordings.  I prefer live performances anyway 

We shouldn’t confuse recordings of concerts with recordings made in halls where concerts are held. While it is true that most orchestral recordings are not made in studios, most orchestral recordings are not of actual concerts. There are few recording studios that can accommodate an entire orchestra in a way that does justice to the music; for practical as well as sonic reasons.

I beg to differ.  Most recordings that I have purchased made in this century have audience noise present.  Resolving systems can detect this well

What I've noticed is that the orchestras' private labels generally use live performances (LSO Live, SFO, Royal Concertgebouw and Berlin Philharmonic, at least in some cases), while most of the commercial labels like Sony, Decca, DG and Phillips still do "studio" recordings, though in the orchestras' concert halls.