OK, I have the picture now.
I wouldn't put the solid coir bottom in it. You want and need the roots to wander out the holes and grip the basket. This plant will get very big and VERY heavy. You will need to rest the stem of the plant, not on the edge of the pot, but farther back in the basket so the stem can grow and be supported.
The only phals I have had in an angled basket were originally grown in the basket sitting on a shelf. I had intended to use them as mounting practice but they grew roots everywhere and I could not get them out of the baskets so I angle hung them.
Here is a pic of one of them - may she rest in peace :>(
You can see how the crown of the plant had grown to the edge of the basket. She had two huge branched spikes. One day the spikes were hanging across the aisle and when I looked, the plant had swiveled to the opposite direction and the stem was broken in two. This is the reason I cautioned you to make sure the crown area of the plant is supported and not growing on the edge at this point in time.
I wish I could help more but I have no experience with using the plastic mount or how to attach it. Back to your original question, the cut up strips of coir would probably be fine for the media, I would just eliminate the solid bottom.
Brooke