Haven't tried that but have noticed that some of the polishes and coatings have Lanolin or "essential oils" in them and don't know the effect that would have on durability. I always check the label.
I used some cheapo clear and it's thicker that the hard as nails. I Iike how the hard as nails soaks into thread but the thicker cheapo stuff has its place/uses as well, in my book.
I got a question on thread sealer of rod wrapping. I been doing some dinking around with broken rods and figured I'd just try the cheapo stuff on the thread. Seems like it does the same thing as the expensive thread sealer and it doesn't disturb color of thread. Question is; if I flex coat over the top am I going to have problems?
I would think depending on how thick you applied it would make some difference. If you only gave it a light coat to seal then it may not be a problem. If it's harder or more fragile than the flex coat it may crack under the FC but I would think that would take some stress. I guess you could always test some on an old chunk of fishing rod or something similar.