I bought a slab and tested it. I'm on the fence. My supplier told me to pour at 180 but I had severe cracking at the top. I also had some wetspots, not the normal kind but it looked like the FO bled out and formed droplets on the inside of the glass. Cold and hot throw were awesome but also had some smoking. While testing this, I poured/tested J50 and J300 using the same exact variables, and found that the others didn't have the bleeding issue. I think if I poured the Harmony Blend at a cooler temp, maybe it wouldn't have been a problem. Anyway, like I said, I'm on the fence. I will probably mix it next time around and see what happens. Also, I used CD wicks. I haven't tested with HTP yet. HTH!