There are a lot of Toscanini’s out there but I don’t have that one. You are really making a strong case for a Tidal subscription. The one I have is the 1953 with the Robert Shaw Chorale. It’s easy to see why Toscanini is the Missa solemnis bedrock but with this one you can literally hear the batton being handed on to the next generation.
The one you want is the live version. There was a studio version done a few days later with exactly the same team but the balance isn’t quite right so some find the soloists too recessed in the mix. Roon didn’t get an identification so this link might be more helpful. A great resource for difficult to source historical recordings. there seems to be a streaming service as well but I haven’t tried it. Scroll past the sales stuff for the review: