Thanks, for for all the input. Oh, that 12-27 cassette was installed in past year with new chain sized for it
and 53/39 chainring. I hope to continue to use it with compact crank. However, I have seen some say that that they use a max of a 12-25 cass with a 50/34 crank.

I guess in the end if I install compact crank, there are 2 possible items to consider:

1.) Lower the FD
2.) Remove at least one chain link