I've been away from SZ for a while and just saw this post. I DO have a Tyros 5 and agree that Free Play styles are great for hymns. However there's a bit of misinformation here...

Free play styles don't "follow" your tempo. They don't have a drum track or rhythmic bass, mostly just pads and chord phrases with a lengthy attack and release so they are quite flexible.

They can be programmed and pretty much duplicated using only SFF1 technology. Ian on the PSRtutorial forum created a free play style that worked on my old PSR-S900.

If you can find Ethereal Movie, for example, available for download, I would try it with BIAB, it might work just fine. Worst case if it crashes, restart and don't do it again ;-)