I've got a couple pairs of rivets. They're a lot more casual than the walts, lower rise a bit more relaxed in the seat with a touch more taper. The taped out seam also makes them look more a lot more casual. I wear them on casual days with a buttoned shirt and on the weekend with a tee.
I don't really want to comment on fit because there is so much vanity sizing in the industry. Your best bet is definitely to compare the measurements to something else, keeping in mind that jeans are normally slimmer than chinos because if jeans hug your thighs and calves it doesn't look so bad but in other light weaves it can look terrible. I'd compare to some trousers you have, rather than jeans.
What colours did you get? The guys one the Epaulet forum seem to have collections of them in every colour!
He's James Boag ...