I'd actually like to see this in stats. I get the impression that these players would mostly play - Vic, Porro, Romero, VDV, Udogie, Palhinha, Bents, Kudus and probably Richi.
Spence has been consistently selected when Udogie couldn't make the line-up and has probably played more over the course of the season.
You would think that when 8 or 9 players play a lot together, then the others would fit around them.
I think the problem is different. I think he is feeling that he has to tweak the system when he changes the personnel, even from the bench. Spence and Udogie are one good example. Bents and Berg another. Kudus and Johnson another. Even Danso for one of the 2 centre halves probably drives tweaks by Frank.
Whoscored.com is a good reference