also you don't necessarily need to keep two entire tups as companions to each other a castrated tup of sufficient age and size will be just as good a companion but remember to run both with the ewes otherwise they will fight when you re-pair them up
generally we allow one tup per forty ewes or 1: 10 if its a tup lamb 1:20 for shearling first timer
when our flock first started we shared a tup with another small flock. running both flocks together for tupping time ( we started with 6 ewes, now have 60)