The MONTAGE can be set to any whole integer tempo between 5-300 bpm, fractions are not selectable using the MONTAGE as Master Clock.

What you can do:
Set the MONTAGE Tempo to 199 (twice the tempo) and count as Cut-time.
If you are using Arpeggios that need to clock sync to 99.50bpm, Set the UNIT MULTIPLY to 200% with Tempo set to 199bpm. This will adjust how they reference the clock Tempo and result in a bpm = 99.50
If you have Motion Sequences, and/or Tempo sync’d LFO/Effects you can usually set them to reference the clock as cuttime.

Alternate Method: Use an external device as your band’s master clock; feed that clock source to the MONTAGE via MIDI (or Audio In); Set the MONTAGE to slave to that Master Clock Source.

On your MONTAGE go to Tempo settings by touching the Quarter Note icon on the top line of the screen.
Set “MIDI SYNC” = MIDI (or A/D IN)
Use a device, or program that can generate Tempo with fraction bpm and set this up appropriately.

For example, DAWs can typically be set to bpm plus fractions. Cubase let’s you set tempo to three decimal places, if necessary.
Set the TEMPO to 99.500
Set Cubase to Output MIDI CLOCK
Go to TRANSPORT > PROJECT SYNCHRONIZATION SETUP... > MIDI CLOCK OUT > DESTINATION > set the Destination to “MONTAGE-1 (Port1)”

If you have a device that creates an audible click connect it to the A/D IN of your keyboard and set the MIDI SYNC = A/D IN.