Welcome, Donna. I think everyone sort of has their favorite potting medium and even rooting medium. Since I grow many hundred tropical plants, I custom-mix all my own potting media. What I do would be difficult and probably unnecessary for the vast number of growers out there.
One thing you need to be aware of is that even in S. Texas (you need to post your USDA zone in your profile so everyone knows where you are), dormancy is about on your doorstep. I stop taking cuttings (to root) mid-September, and know that some/many of those cuttings still won't have enough time to root before dormancy sets in. Also, be sure that your rooting media stays completely dry. I use 100% coarse perlite. There are no roots so your plumeria can't utilize moisture. Thus rot will be the end result.
Back to potting a rooted plant. I would purchase something like general purpose potting mix, and at this time of year I would get one without any fertilizer. Use 1/2 potting mix, 1/4 coarse perlite, and 1/4 cypress mulch (or orchid media if you wanted to really get fancy
). When I pot up my newly rooted, or even up-potting my plumeria, I want a somewhat moisture retentive media but one that drains easily and quickly.
Most tips/branches will have those tiny, terminal leaves, what I call "claws", if that plant is actively growing.
All the above is simply what I have learned by growing plumeria for 25+ years. There are others with more experience and I am sure they will chime in with their own remarks.
