Was just having a go at fitting these to the actual real time signature.
I tried the 54_SWING.STY 5/4 over 1 bar and I add 25% to the tempo in Biab that is 130bpm based on 4/4 I get 162.5bpm so I set REAPER to that then the audio will fit if it has no Acid info added.
The midi I had to set the playrate to 0.8

If I have a 12/8 style spread over 2 bars @120bpm I set REAPER to 90bpm -25%
The midi I had to set the playrate to 1.333
If it's over 1 bar then set tempo to 180bpm
The midi I had to set the playrate to 0.666