Make a studio profile, turn off cab, test. Adjust, reprofile, test. Adjust, reprofile test.
Even better, mic and record your amp to your liking and use that as your control. Don't touch the mic, profile, record second track through speaker and mic and compare. Adjust, reprofile and test until you get it identical. Tedious, but worth the effort
I realize, in your mind it may not seem as "pure" as getting a direct profile, but it doesn't matter how you get there...as long as you get there