Welcome to the forum.

There is a reason that there are so many vintage 5/8 and a slightly lesser extent 6/8 straight razors on the used market. They are less costly than the bigger sizes and do the job nicely. I do not recall seeing a barber using a large sized blade back when they were giving straight razor shaves. Personally I lean more to a 6/8 size.

IIRC the barbers back then were using full hollows and they shaved every imaginable beard type with them. Long story short, medium sized full hollows will definitely do the job if you do your part.

The factory edges on modern production razors can be hit or miss. For that reason I would suggest buying your razor from a reputable retailer who hones them to shave ready in shop prior to sending them out to customers.

Although I lean towards full hollows, I do shave with everything from them on up to near wedge grinds. They all will do the job with a shave ready edge.

Bob