I've just bought a Virago 535. I test rode it yesterday and it was fine. The chap in the store said I was too big for it, however I like the bike so I'm going ahead and I collect it on Saturday.
I'm 6' 2" and 14.5 stone. My outgoing bike which I have PX'ed is a Honda CMX 250 and I rode that OK and found it quite comfortable. The Virago seemed quite big in comparison. I wanted something with a bit more power and I've always liked the 535, so I'll let you know how I get on.
I'm not sure about the differing seat height between the 535 and the 750. I've never sat on a 750
Regards