On the north area of the battlefield the CSA guns were never very effective. I hope the point is that an unsupported infantry attack by the ANV's 2nd Corps would have been costly if resisted, and would have been even if undertaken as soon as possible after being directed by the commanding general.Okay, so you've assigned four or five batteries to delivering long range fire against the Confederate 3rd Corps. Call it 27 guns.
Now think about how many casualties you're actually expecting those ~27 guns to actually do.
As for the 2nd Corps attack, well, we started with 54 guns so there's a maximum of ~27 guns on that side as well.
You've previously indicated that the thing causing the casualties would be "the guns that the Confederates could not answer", but guns cause casualties over time - so you'd need the Union infantry on the ridges to be capable of holding back the attack more or less by themselves to create the situation where the Confederate troops are in the area to take casualties.
(This is before considering that the Confederates did actually have guns as well - 3/4 of the Union number in their army - so I suspect they could in fact "answer".)