I have some fixed opinions on lightfields and copper solids based on failures.
Lightfields are great. I love them and use them occasionally in my Ithaca (usually use winchester forster slugs). Unfortunately the rim brass is very soft. The extractor on Remington autoloaders will peen the rim during the course of chambering and unchambering lightfields. The administrative functions of loading and unloading in the field for safety sake will eventually bind up your action. Not only will you not learn this on the range since all rounds chambered are typically fired, you will experience this during hunting at the most inopportune moment, guaranteed.
It has happened twice to my hunting partners with 11-87s. I have ceased using lightfields in my 11-87 for this exact reason. They're fine in my Ithaca and I continue to use them with great success. I suspect you won't have any issue in a mossberg either, however I recommend you inspect the rims on rounds until you're satisfied they're not disfigured or distorted.
Copper Solids:
When I bought my 11-87 I tried half a dozen different types of ammo, 2.75" copper solids shot best, so I purchased a case. I rue that decision. Twice I shot deer at extremely close range only to have the slug super expand and fail to penetrate. The first was a 150 lb doe. I hit her on the point of the shoulder quartering toward me, 10 yards away. It only one lunged her. The second a 200 lb doe I chest shot from above. I chalked the first up to abnormality. After the second I began to have misgivings. That same season my hunting partner put 3 copper solids into a broadside buck on the move. Not 1 of them exited a 150 lb buck. Not 1.
I would not recommend copper solids to anyone.
YMMV.
Oh BTW, to the OP, one of my hunting buddies uses a 500 with a rifled barrel. He uses plain old winchester forster cup slugs to great effect. As always, try a few brands and see what your gun prefers.