Q: Auto-moving RT processes to isolated core with RT kernel

I do not recall reading anywhere that RT kernel benefits from isolated cpu's but read plenty about RTAI benefiting from it. I never ever tested it or any other tricks listed to improve latency as i do not like using best case scenarios and ending up with something messed up later, i just stick a UBS and run live version of what i need, RTAI or RT and check the latency for bout half an hour while molesting the computer properly with youtube, glxgears, hdd speed test, simple scan, media player etc. If i get decent numbers i move on, usually i do. The one thing i noted on plenty of computers is i get much better latency numbers running live from USB than form an actual install on a HDD. Lately using SSD i see no such issues. I however do disable everything related to power saving, wake ups, modems, serial ports even sound cards in the BIOS, and that does improve things very much, especially on IBM T42 and X60 going from 60000 to 115000 down to rarely above 15000.
This is all just my experience and i am aware that it is not an answer to your question, but related to it.