I went with Tom Langdon's 2 barrel Holley/Webber carb, which is what Pinto's came with. It's really an excellent carburetor that works a LOT better than the old OEM 1 bbl's.
Some people use two of those on the twin carb manifolds. Then you get 4 barrels. I didn't because at my high altitude, I'm afraid 4 barrels on a 3800 rpm 235 might be over-carburetion. Also, you can't get the jets new anymore. But being brass, you can solder them and re-drill the holes with what you need easily enough.
And I don't know that the modern carbs require as much pre-heating from the exhaust as the old carbs did. My Holley/Webber is isolated with a half-inch carb spacer, and except for about a minute of warm up time on cold mornings, it doesn't seem to miss it.
I'd say pretty fearlessly that if you have a modern carb, you probably don't need to worry about the heat riser. But if you run the older carbs, you'd better have them.
