One small thing to bear in mind - phone wire is multi-strand so won't necessarily hold a bend if you want to keep wiring in a certain position, it flexes.
Single strand equipment wire is cheap as chips on e-bay, I got a pack of several colours, 5m of each + 10m black & red 26 gauge for about £4.
The phone wire is ~0,5mm conductor diameter when twisted, solid core is available in 0,2mm 0,4mm 0,6mm etc.