as others have said, make what looks good to you.
there are lots of examples out there, look at as many as you can, and you'll see the 'bad' examples too! ( black letters on a dark brown panel etc.)
Millions have been spent on 'the most legible' lettering studies. Look at a highway sign....most states & provinces are converting the old 'highway gothic' to this font......(to the layperson, yeah, it's a lot like arial or helvetica medium.)
the latest flavour is called 'ClearView' , and exhaustive testing showed faster recognition and longer viewing distances, always with upper and lower case.
that said....esthetically I agree that a nice line of all caps has a certain formaiity to it... I mean, you know it says 'MASTER' not 'Mister'.
If you use some simple design software, it's easy to condense the longer words to reduce the need to abbreviate or hyphenate. ( if you're not savvy, your 9-year old neighbour can help!)
keep in mind, after a few months, you'll want to change something!