SOPP285: How should I play Bach on smaller church organs in buildings that have flat acoustics?

This question was sent by John, and he writes: I’ve almost learnt In dulci jubilo by Bach, your training videos have been so helpful thank you! It seemed a really daunting piece to learn, but its coming together quicker than I expected, all the sight reading has helped me and your teaching has really helped me improve. My question is how should I play this piece on smaller church organs in buildings that have flat acoustics. When I played my recital on St Johns organ in Vilnius, it was an incredible eye opening experience to play on a large mechanical organ in a huge acoustic. I came to realize how articulate legato suddenly made sense playing on an instrument closer to Bach’s time in a resonant acoustic. When I listen to other professionals play this piece in large churches or cathedrals, I can hear some parts get lost in the blend of legato. But when I play it in our church, I’m worried it sounds a bit too staccato and the gaps between the longer notes sounds a little disjointed. Can you give some advice about playing Bach in flat acoustics? Should I try to play more legato? Did Bach ever use finger substitutions? Would I have to play it faster in flat acoustics?