Landis K- We need help leather band left side measuring

[ChrisMarquez]

Ok, so the new puppy must have thought the leather band was a pupperoni treat and took some chewing to it. So now the band is short. 
I have replaced the leather band when the length of the entirety is worn but have the old one a a guide for length cut, easy enough. 
Double checking with you all here on cutting a new band the proper length, not too long, ok, too short, on no! 
Would running string looping the circuit between the wheels work for measure twice cut once method?

This Landis K has the rear spindle at ground level. So when facing the K it is the left side hand wheel going down to the spindle wheel. Thank you in advance for any tips. 
 

Chris