Rough idle

204/204/110+4 @.050 270/270 HFT
Oh yeah that will idle "rough"
It has 50* of overlap, and in at the spec of 106, the Ica is 61.5
It's kinduv a poser cam sounding a lil bigger than a 340 cam, but the power comes in a lil sooner, but not as much, so that's all good
But that 50* of overlap is not made for log-manifolds.
When the exhaust piles up in the logs, it will seek the path of least resistance, So at the end of the exhaust stroke , the exhaust valve will still be open for another 21.5 degrees and the piston is just starting down on the intake stroke, so there is a good chance that some of that exhaust is gonna back up into the intake at idle, and it's going the wrong way!
Or if the log gets pressurized, it can/will puke exhaust into another cylinder with an open exhaust valve.
Furthermore, after the piston hits bottom on the intake stroke, it will be another 61.5 degrees before the intake valve reaches it's specified advertised closing point, but the actual on the seat and not-leaking point ,could be more than 10 * later; So, the piston,at idle, is gonna be pushing some of that just inducted F/A charge back up into the intake.
Between those two events, your intake is gonna be full of crap going in all the wrong directions for it to idle smooth. That cam really needs headers to straighten out the idle airflow. Or, it's gonna want to idle at a higher rpm than usual, to reduce the amount of time for all this to happen.
All that to say that 750idle rpm may be as good as it gets, and whatever it's got for smoothness, may also be as good as it gets.
I think 14* of idle-timing is about as low as you wanna go with that 270* cam.
Before you do anything more on the carb; check your hot start. If it goes click-vroom and starts right up when you twist the key, without touching the gas , then I would leave it alone.
But if it cranks a bit before firing up or you have to give it pedal, then;
I would try 12*, and reset the mixture screws to 2.25T, and open the throttles a tad more, then see what happens; but I think you are pretty close. Make sure the wet fuel level is right on, and stable.