That is very pretty & does seem happy.
Through experience over the last 2 years i have found that overpotting is not really a major issue with s/h with Phals.So mine tend to go in larger pots than what i would use for bark.Also i use taller pots than with bark & this seems to be a winning point for Phrags.
I killed a
Phrag besseae &
Phrag Tara in s/h , they just kept loosing leaves until they just dissappeared.I bought a new
Phrag Tara & tried the same size pot as some of my larger Phrags & it has kicked out 2 new growths & is growing really strongly.
What i use is a 6" clear pot & a 4" clear pot.
I cut the base out of the 6" pot & sit this in the 4" pot , a little tape keeps them together.I then sit this in a !" deep saucer as a res.
I was going to try 1 off the first plants i bought in the taller pots(
Phal Cool Breeze) but it has decided to spike through the centre of the crown so i,m probably going to lose the plant.
This
Phal has been in the same pot for 2 years & has not been repotted.The roots are so numerous i have to tape the supporting sticks to the outside of the pot.This flowering it has 2 spikes with 3 side branches each(about 30 buds/flowers).I would take a piccie but my sister pinched it when i was semi-comatose after a heavy night on the tiles.
I bought a
Phal Everspring King"Lee" from a private collection & it turned out to be a basal keike(original mother plant was just a dried nub) but i paid very little for it.It was in quite a sad state root wise.The medium was like sludge @ the bottom of the pot & had only 1 good root.
So into s/h it went.The pot is 6 1/2" high(1" res) x 5 1/2" dia.Plant has a leafspan of 6".

Massively overpotted but look @ the root growth & the new leaf.I,ve had the plant since the beginning of Feb this year so i have high hopes for it doing well.
Phal gigantea is known as a tricky plant to get growing well.Mine is in a 8" plastic pot & when i put in s/h this time last year the leaves did not reach the outside of the pot.

Even though temps in my growroom do go below 60f during the winter it is growing leaves really quickly.
s/h the wonder medium ?
Not a chance !
But it is worth a little experimentation.Not all my plants are in s/h(i have 1 paph out of 25 or so in s/h).
Oh yes medium is Hydroleca , it is used for topping benches.