If you are really worried about stressing the bucket lip when welding on chain hooks, just make a reinforcing pad to put on the FEL bucket then attach the hooks to the pad. I didn't have any scrap of sufficient thickness when I put hooks on my LS, so I found some brackets made for attaching springs to trailer axles. They were 4"x6"x3/8" thick. I welded them all around onto my top lip of the FEL, then welded the chain hooks to the pad. I have used these with a chain to lift the front end of my 1/2 ton Chevy truck off the ground and no movement of the hooks.
For these small CUT's which may be capable of lifting 800# at most, you wouldn't need that thickness of pad but the size should still be similar so any weight would be spread over a larger area. I would think at most a 3/16" thick 4x4 or 4x6 (whichever fits the top best) should work well.