Custom Navigation on Master Slides

Hi all,

Here's the long and short of it...

The short: Are the Master Slides the most practical place to put buttons and layers containing menus and navigation, or does it make more sense to place the buttons and layers on each individual slide in the module and just copy any transitions and triggers?

The long: I'm starting work on a set of modules where I am required to have 3 buttons up the top of each slide (Help, Resources, Navigation) which will prompt a menu from the top of the screen containing the relevant information for the learner, which will then retract once the learner closes the menu. The modules also require the next and previous buttons to be inside the course, as images with separate states to match a style guide.

I've been doing these buttons on the Master Slides and all the buttons and layers work as they should, but I've encountered some issues, such as slides which don't require the next or previous button (but it being on the master and therefore visible), or slides where I don't want those buttons to display until something has been done. Additionally, I've been putting the 3 top buttons and the menu that comes from those on the Master Slides also, but would prefer if I didn't need to place it on every slide type separately and also not having to make sure that if I update the content in the menu on one then I update every version.

Is there a better way to place these buttons? The 3 buttons up the top of the slides also has a layer for each button, which contains the menu that drops down from the top.

Hopefully that makes sense!

Thanks in advance.