Interesting to see others in our State using slugs to achieve their hunting needs. I became interested in slugs a decade or so ago because a local and a not so local public hunt required them. The smooth-bore requirement of the ACoE does add a bit of a "lack" of a twist to the shooting. My interest in the ammo is handloading to fill the requirement, but I have shot a bunch of factory ammo.
I've owned several slug-guns and for rifled slugs have settled on the Marlin 512, outside the interest of this topic. I have two smooth barrels for my 50+year-old New Haven 600 a discount store (purchased at Gibson's) version of the Mossberg 500. With any smooth-bore you shoot, quality sights are essential, a front bead will not deliver projectile shooting accuracy. I found smooth-bore barrels very cheap for the Mossberg 500 series, everyone what rifled barrels, mine was $50 shipped via eBay. The Mossberg barrels have an excellent adjustable rear sight on their smooth-bore barrels.
As I noted, I've shot a bunch of brands of ammo, store-bought and ordered in, and hands down what I've found that shoots the best is
LightField's Hybred Hunting series. It is a single hole shooter from my smooth-bore New Haven. It is the standard by which I judge my cast, handloaded slugs.
They are not cheap, but once settled in, you probably won't shoot a lot of them. I buy them through Bud's as they have fixed shipping on ammo ($10) and slugs run up the shipping charges fast.
I looked up the ACoE shot requirements, and I don't see the "(buck)shot larger than #2" an issue. I started hunting feral hogs at night in 1978. I was around some Hill Country oldtimers, we hunted long, baited cross-fences on full moon nights, and they laughed at my buckshot. They said if I wanted to increase my success at the shot, to shoot BBs. I did not doubt the guys and bought a case of a thousand rounds of it. A BB (.18") is larger than #2 (.15"), but I don't think .03" is going to matter. I think you will kill the heck out of them but choke and sights are important. I've stalked and killed a lot of hogs with Express loads of #6 shot. This all started long before deer feeders where common, but I still use BBs on hogs under lighted feeders. I've seen friends take a feeder leg out with buckshot, but I've never lost a leg to BBs. I've never played around with that 1K of ammo other than to pattern a barrel, probably less than ten shots. I've got less than a dozen left. Below is a typical single shot kill under a feeder. My 26" full choke barrel will keep every BB between the legs of a feeder at 35-yards.
For your bench shooting, wear a life jacket. I bought this at Academy on sale for less than $15, and it makes a difference with the slugs.
Be careful with the recoil. I was shooting a lot of slugs late last year and one eye started to bother me, I was seeing a lot of floaters. I went to the eye doctor and was told that my retina had a lot of small stress tears. She asked me if I boxed or was involved in physical contact activity where blows were delivered. I said no, but remembered that Mr. Lee of Lee Precision had to stop shooting heavy recoil firearms for this reason. I didn't mention the shooting, but I could tell she didn't believe me. She said whatever I was doing to lighten up and they would repair themselves. I limit my slug shooting to 15 shots a session now, and the problem hasn't returned.