I recommend that you just get used to dribbling the final grain or two for the large capacity rounds.

For my .375 H&H I dump my measure twice into a scale and then dribble the balance to suit. Unless one does a lot of large capacity case shooting one can get along this way easily.

I usually shoot the .375 about 50 times a year to keep in fun and giggles and the smaller powder measure works just fine for this trick. I gave up looking for a more accurate measure years ago....there just isn't one unless you're throweing ball powder and then almost any measure works well.