Retune my entire carb after installing new heads?

That is a BIG cam & the large rod/stroke ratio of the 440 doesn't like big cams.....
So your high idle speed is not surprising & I think it is about right. I doubt there is anything you could do to get it to reliably idle slower....
I would expect the lash increase due to heads warming up would cause the idle rpm to increase because you are in effect shortening cam duration & increasing vacuum [ carb signal ].
I would also remove & plug the PCV to eliminate it as a problem.

What heat range plugs are you running? Have you got another carb you could try?