My grandater used to tell me, "If it ain't broke, don't fix it!" If you're getting good results with the 7/8, it must be an OK size for a beginner.

Bigger blade is usually a bit heavier. I find them easier to work with. But referencing Euclid's post above, I also wear an XL glove. And that's a tight fit. I go XXL when I can find them.

Most of my blades are 5/8. A few are worn and less wide. 4/8, maybe less. Takes a little getting used to but once you've got a handle on it they all shave.

I think I just like the bigger blades because the weight makes them less prone to 'bounce.'