Sometimes the less said the better when talking to someone in cult mode.
I found that once I had my little say and then stopped talking, THEY brought the subject up and I let THEM do the talking.
Sometimes as they were defending their beliefs and I quietly listened and said nothing, you could see that they were realizing how ridiculous their arguments were.
If you let them know that you simply want to understand rather than to prove a point or be right, they let down their guard.
In the case of Lett's pinky ring you could have casually said, for example.
You: " Bro. Lett always looks sharp but I don't know.....something about him wearing a pinky ring, doesn't sit right with me"
Wife: How so?
You: " Well I'm probably not seeing things correctly or being overly critical but I suppose it's because I'm thinking about Jesus' message of modesty and humility and about all those in this audience and in audiences around the world who are living meager existences because they are putting kingdom interest first in their lives or because they live in impoverished lands. It seems like sometimes a pinky ring is something a person with excess in a material way, wears and it sort of sends the message that the wearer thinks pretty highly of himself or of his position in life." Or maybe it's just because I saw that video where they are encouraging little kids to put their pocket money in the contribution box rather than treat themselves to an ice cream and seeing him with a pinky ring makes me think he's not really sacrificing much himself.
Wife: "The Bible says noting about the wearing of pinky rings and besides, he's speaking to large crowds of people and needs to look his best and look like an authority figure"
You: (nodding in agreement) "Hmmm....yeah...I suppose I can see how that could be the case. He does need to look like someone who knows what he's talking about "
If you make sure to let them know that you are questioning your self rather than their beliefs and leave it at that, often they will feel like they've done their duty by defending their cult and will at the same time hear the holes in their own logic while doing so. Over time they'll begin to notice more and more of these holes and will begin to question things as they hear them on their own.