You won't like this but I absolutely HATE the practice of giving sons numbers like
William John IV. To me, it looks ridiculous and pretentious. Maybe it's because I've grown up in Britain where nobody does this and the only people who have numbers after their name are members of the royal family (e.g.
George VI)
I have a friend whose father is the 7th
Thomas James (known as Thos) but he would never write his name as
Thomas James VII. I think it looks ridiculous.
As for naming a son after his father, it's not something I'd do, mainly because I think it's a bit boring and could be confusing. If I married a man whose family did that I would only do it if the family were desperate to continue this tradition and only if I genuinely liked the name (i.e. he was called
Benjamin or
Alexander) or if we could call the son by his middle name. I can't really imagine why anyone would get that worked up about continuing a name and if they were, it would probably make me more stubborn and fight against it!
I would, however consider using the father's name as a middle name. This is fairly popular over here and my brother has my dad's name as his middle name. Seems to be only a tradition for boys. I hardly know anyone who gives the mum's name as a mn for a girl. Maybe because women aren't so bothered or maybe because their names usually date more quickly.
My friend gave her son her husband's fn as a mn (
Ethan Russel) but didn't do the same for her daughter (although the mn had the same initial -
Abigail Louise not
Abigail Lesley).