We can use speed brake w/ flap, the limit being F-10, or F-20 depending on the tail #. Older -400's are resricted to F-10. It's still an airmanship issue as how much to use, as rather large sink rates can develop, whilist outside the GPWS envelope. If you forget the boards, when the thrust comes up you get an EICAC message and wailer.
d.