Shawn- Regarding a chunk of your first question. Two excellent sources of information are:

Dickey, Thomas S.; George, Peter C.
Field Artillery Projectiles of the American Civil War
(See if you can get the 1993 edition)

John Gross Barnard
Notes on Sea Coast Defence
ISBN:1402133952

Barnard was the engineer whose work you still walk through in many of the National Parks of this country. The text covers artilley and the structures they are meant to batter.
Detailed reference to the work of Maj. Rodman.

For primary records of the greatest artillery barrage of the US Civil War see Series I-Volume 18 of the ORN. The bludgeoning of Fts. Jackson and St. Philip over the course of a week in April of 1862 constitutes the greatest weight of fire projected in the conflict. Over 8000 rounds of XIII inch mortar expended by the flotilla of Com. David Dixon Porter.