Well, people with 3D printers don't really have a good excuse to be battling with scaling issues when it comes to props. The only thing you do is to create a center slice of the prop, 2 mm thick, and print that to the scale you hope would fit. It will be printed pretty fast, and you'll have a perfect reference part telling you exactly how the full part will behave.
Don't want to do that ?
If you'd do a prop in any other manner, I'd suppose you'd do exactly the same : take a piece of cardboard, draw it out and see what fits you. Then start scaling to your needs and create the thing in whatever material you chose and in the case of a 3D print, scale the full part in one go and then slice it up to fit your machine. That is the best way to avoid "oopsies" during the process.
It's not because it's 3D printing that this suddenly can't be be done prior to printing stuff out no ?
That being said, I would have no issues using a prop that size. Is it big ? Yes it is. Is it
supposed to be big ? Yes it is. Does your hand fit in the grip ? It does,
perfectly I might add.
I don't see the problem.
Clearly on the picture : Neither does Tigger, as he shows he's over the moon by the display of your armour and weapon. Always trust the judgement of felines when it comes to looking good, they're born to look good so they
know about this stuff.