In hyperkeys mode, just press "f" for find, and when the box pops up, you type in the word that you want to find and the word you want to replace it with and click enter. It will go to the first instance of that word and ask if you want to replace it in this instance, and you click yes or no. Then press Ctrl+L to go to the next instance, and so on and so forth until you've found and replaced all the instances of that word.
I'm not sure if this is the answer you're looking for because it doesn't involve globalling, but it is an easy way to find and replace a word. Hope that helps!
You probably got enough information. As a legal assistant, I did MANY 20-page briefs. I did a lot of find and replace. Example: Kringle. REPLACE with Xs (because there are NO words together that are Xs). Then REPLACE Xs with Krinkle (the name it was supposed to be).