IMO you could do it right now during dormancy.

I begin cutting in late February which gives me time to callus and then begin planting in mid March.

I will need to cut my plants as well. Any suggestions on where should I cut the stem... how many in above the soil? I've got one stem plants that have never bloomed.

Veronika, If your plan is to cut the top part of the single tip plant off to promote (does not guarantee) branching then I recommend about 8 -12 inches above the soil and at a point where you have numerous leaf scars. The height you cut is really dependent on growth habits and how you want the plant to look. Those scars will be the point where new branch(es) will hopefully start so you want as many as you can as near to your cut as possible.

By doing this you are essentially ensuring another year without this plant blooming.

I want to start a plumeria for a friend of mine so I'm planning to get a cutting from one of my plumerias. Which part should I use for my cutting(also for the benefit of the plant), also, how young/old should I cut it from and does it make a difference ?

I'd really appreciate help/suggestions !!! Thanks in advance,

Annamaria