Spindle indexing disc with opto switches

I'm about to make an "encoder" from a disc and 2 of these opto switches RS 306-061. uk.rs-online.com/web/p/slotted-optical-s...rigin=PSF_438299|alt

I'm not too concerned with the single pulse index as already have this up and running and can be left as is I think?

Is the best number holes/slots 100? Comments on the choice of sensor most welcome as don't want to waste precious time!

Thanks

they are fine , for me i'd go with a disk of 120 slots ,
however , any number of slots from say 60 will do
i have used disks with 100 , without problem

( i say 120 for the reason that it's equally divisable into 360 degrees )
all depends on how much space you have available for the diameter of the disk

120 it is then - makes total sense. Aslong as I can get them in, obviously I could make the disc bigger if space allows?? Is there an ideal gap size between holes/slots, or maybe a minimum gap?

cheers