You can look at my 10G i just added 3 SPS frags.
It's only 2 months old.
Your tanks is like 20x more beautiful, and probably 15x more established.
I'm sure you will have 0 problem with this sps man. your husbandry is out the roof.
IME. SPS just want stability. Dirty or Clean, not as big as a deal as stability. Sudden shift from dirty to clean, or clean to dirty is what kills them overnight with RTN.
If you're using GFO, dont change that, etc etc.
Dont make any MAJOR changes. After adding the SPS. If there's somethign you want to change, change it now and then wait a week.
I think you could remove all the xenia, and be totally fine.
Also jsut realize if you take bioload out, reduce your feedings, that alone is going to make big differences and help offset any kind of swing.