Pedestal Drill belt fitment help.

Recently bought a second hand 6odd foot pedestal drill. It is an older proper cast iron job and was an absolute steal at only $40 as it was covered in surface rust. Anyway, after a thorough going over, cleaning and oiling it has come up great and thankfully no shaft play.

The only thing is there are no belts. It is the twin belt type with the 3 pullys each with 4 'ribs'.

There are no identifying marks on the drill other than the pictures for the belts adjustments re speed increments.

Do these style of drills have a 'standard' belt length, type?

If not, what method should I use to determine the lenght of the two belts?

Are they the same length?

Thanks.