There is no reason why it would not work.
I mount a lot of Phals (remember they grow down naturally not upside down in a pot)
Watering is not a problem if the plant is outside, just hit it with a hose often. They dry fast mounted and Phals like to be moist. Fortunately root rot and Crown rot and not problems with mounted Phals but drying is a problem.
You might like to mount it on a piece of wood and be able to carry it in the house when it is in flower. Taking the rubber tree inside is not possible when they get 20 feet high.
If your rubber tree is potted inside, you need to consider the issue of watering the Phal. Then definitely mount it on wood where you can take it off and dunk it in a bucket of water.