I'm studying for a General supervisors' exam.
Along with the NEC Code book it is allowed to bring a reference book. On my last test I took the Ugley's reference. But I'm looking for opinions on weather I'd be able to move along faster with a different book like Ferm's Fast Finder, or Tom Henry's Key word Index. I've never looked at either but would be willing to buy one. Opinions greatly appreciated.

The best advice I can give is to know that book from cover to cover. I did not use either when I took my exams, but I hear Tom Henry's Index is good. I don't know about the other mention reference. As I remember our test, we had 1-1/2 minutes per question average. Some take more time, some take less. I finished with only a few minutes to spare on my Masters Exam. I finished so soon on my Journeyman exam that I was really worried.
There are several books of problems out there. Study those for several weeks before the exam. You will learn where to find it in the Code book a lot faster. Practice with the 1-1/2 minute per question in mind.
Good luck to you.
(Someday I may learn how to use these "Smiley" faces.)