As with many organs, it’s best heard away from the console and when not playing it ! When my little piece was recorded there by Regent, most of the mikes were on the floor of the nave, albeit somewhat elevated. It is, nonetheless, more than good at the console. Marvel at the size of the gallery.
You can see from the console photo on NPOR (I can privately send you a better one), there is a sufficiency of aids to registration and coupling, etc. It should be noted, however, that the action is quite old and slightly ‘clattery’. There was a plan to raise, I believe, well over £1,000,000 for a complete refurbishment.
Having said all of that, it is a fabulous instrument in the most gorgeous acoustic, which is more than close to St Paul’s. It should prove one of your best organ experiences and I, for one, will be interested to find out your impressions.
If you don’t mind a few suggestions, compare the choirs of strings (Choir, Swell, Solo), the reeds (Great, Swell, Solo), the diapasons (Choir, Great, Swell), for example. The alternation of these was employed to great effect in the registration of my piece.
Finally, use some minutes to walk on the 'ground floor' and soak in the beauty of what is, in effect, a basilica . . . imagining how poly-choral Gabrieli would sound there.