Out of those 2, I’d personally go with the
SNM sliver for 2 reasons:
1) you don’t have to cut out/mess around much with with body of the bed by going with the sliver (unlike recessed lights)
2) since the sliver is cheaper, it’ll be easier to replace in an area that is
IMO more prone to damage than most other areas where lighting is installed
However, if you have the money, I’d recommend you consider the Sound off M power fascia 6 LED (4”). It’s slim, has a silicone-type housing that’s more rugged than a typical poly lense, and it has dual color functionality if you want it to have solid clear override for extra scene lighting (combined with amber flashing for warning)