Gage's Battery was Company "B" of the Alabama State Artillery, this state's equivalent of the Washington Artillery of New Orleans. If any artillery organization from Alabama did things by the book, it was the Alabama State Artillery. I have not looked at the regulations, but it appears that six artificers were the maximum specified for a six-gun battery.

Apparently different types of tasks were expected of each type of artificer:

March 5, 1862
Avery R. Preston, [15th Independent Battery, Ohio Volunteer Light Artillery], Paducah, Kentucky. To Governor David Tod. Letter stating that in December 1861, he enlisted under Captain J.B. Burrows with the express understanding that he was to be 1st Artificer in iron, that owing to the state of his health, he was to be exempt from horse shoeing, that the unit was to be a 12-gun battery under command of Burrows, that soon after he came to Camp Dennison, he was taken sick and sent home on furlough, that when he rejoined his battery, he was told that he had been superceded, that Captain E[dward] Speer, who had taken command of the battery, enlisted a Mr. Darling of Warren and gave him the post of 1st Artificer in iron, that Speer also enlisted a Mr. McChristian (another blacksmith) as Artificer, that their battery now had four Artificers in iron, one in wood, and one shoemaker who went as saddler, that it seemed wrong to him to have so many Artificers in iron as two could do all the work and more....

http://www.ohiohistory.org/onlinedoc/civilwar/sa0147/28_04.cfm

At some point in the past few years I collected equipment reports for the batteries belonging to Withers/Anderson's Division of the Army of Tennessee. It's interesting to consider how much equipment/transportation/ammunition was issued to each artillery company. Here's an example, being an Arkansas battery earlier in the war:

PULASKI ARTILLERY.—List of property turned over to Col. Hindman September 2, 1861, by Capt. Woodruff:

Two 12-pound Howitzers (bronze) and equipments; two 6-pound guns and equipments; four caissons; one battery wagon, one forge wagon, twenty-nine sets artillery harness, five sets wagon harness, nine saddles, nine bridles, one set carpenter’s tools, one set blacksmith tools, one keg powder, one lot iron and steel, assorted, one grind stone and gearing, thirty-four wagon spokes, nine fellies, one can neat’s fot oil, one lot buckles and nails, one lot beef tallow, three sheep-skins, one box black lead, nine picks, one dozen bridle bits, one lot extra harness in battery wagon, nine spades, two forks, three horse collars (extra), three Jack screws, eight axes, three sponge heads, one rammer head, one box horse medicine, one box battery equipment, one box currycombs and brushes, fifty-six horses.

"Received of W. E. Woodruff, Jr., Captain Pulaski Artillery, the articles mentioned in the foregoing list, being part of ordnance, etc., transferred by the State of Arkansas to Confederate States. These articles are not in first-class condition, but have been used in the State service during the existing war. (Duplicates.)

(Signed) "T. C. Hindman, Col. C. S. A."

It seems that Confederate artillerymen were always short of horses and proper feed to keep their animals up to strength. After General Johnston took over command of the A/T he reported that the horses of some batteries were not strong enough to pull a gun over a moderate-sized hill.

Lest anyone be confused by my first statement, it is true that Gage's Company was assigned to the 2nd Alabama Artillery Battalion as Battery "E". However, prior to that time it had organized as Company "B" of the Alabama State Artillery. Company "A" of the State Artillery was Ketchum's and later Garrity's Battery, which served with the Army of Tennessee. In my opinion Garrity's and Dent's batteries were the two best artillery organizations this state produced for service in the Army of Tennessee.

For what it's worth, when I visited the Smithsonian 2-1/2 years ago there were some sketches of Gage's Battery in action at Shiloh on display. These were done in pencil by a lieutenant who served with the battery. If I recall, guns appeared to be mounted on older (pre-1840), double- trail field carriages.