Actually, 44mm isn't too bad. 50mm is pretty good and IMO, 56mm is overkill. As always, there's much to consider.

First, quality of glass is every bit is important as OD. If I were forced to cut, I'd cut the objective size before quality glass.

Next, think exit pupil. What magnification are you looking for and how old are you? The eye can only accept so much light and the older you are, the less light they can accept. Unless you're looking long-range high magnification, 56mm is simply unnecessary.

Finally, there's weight and bulk. The larger the OD, the more weight that you're packing in.

I hope that's at least some food for thought for you.