There are three factors that you should consider when choosing a large watch (in my opinion).
1) The shape of your wrist is the first to consider. If you have a wrist that is flatter/broader, a larger watch may work well since it has more area to sit against.
2) The watch measurement lug to lug is the next thing I would consider. The lugs should not overhang your wrist as the strap would sit awkwardly and could make the watch uncomfortable to wear.
3) And closely related to measurement lug to lug, the next thing I would consider is the shape of the lugs on the watch you are looking at. The more they curve down, the better your chances are that the watch will look fine on a smaller wrist.
To give some examples- The Breitling Montbrillant Legende is a big watch at 47mm, but as many here have demonstrated, the watch works well on a smaller wrist due to the lug contour. On the other side of that spectrum, a 42mm AP Royal Oak Offshore does not fit comfortably on the wrist because of the shape of it's integrated lugs, and ends up wearing like a much larger watch (especially on smaller wrists).
My advice is to see if you can try on one of the watches you are interested in prior to buying. If that's not an option, you can always buy something in the trading section that's already suffered first owner depreciation and if it doesn't suit you, you can list it for sale again.
Heh... With that last paragraph in mind, I think this kind of situation makes for a good reminder as to why some people get into reps- Test driving certain pieces in this fashion is far more affordable than doing it with gens.