Welcome to SRP!

Choice of width is basically a matter of personal preference, and is something you just have to figure out.
I prefer blades that are 6/8 or larger, generally because I feel I have better control over larger and heavier razors both when shaving, stropping and honing.

A 5/8 or 6/8 are the sizes that are generally recommended when starting out, these are middle sized and easy to use. Both smaller and bigger blades requires some sort of adjustment in use, with the the smaller ones it can be a bit more difficult to control the angle while the bigger ones makes that part a bit easier, but they are often heavier and less maneuverable.