As always you need to try it but when I had a Flatcap X I used it solely on a CD5X. Try it on the CD5X first and then add another item to the mic and see if the sound improves overall or not.
I must say I’m impressed by the 5X w/o FC so looking forward to trying it with.
I’ll give both/all options a try on my next couple of days off…I have to resite the rack anyway so that will give me the opportunity (and sort out the rats’ nest of cables that has developed).