About the glove thing- that's why I posted about it, to confirm that if you're going to try this product it's best to use gloves. The directions recommend it but it's not absolutely necessary as it can be more difficult to apply with gloves. My hand was just dry for a bit, nothing serious happened. I'm still alive.
I would say the reason they insist, or suggest to flat iron at 450 is to get the full potential out of the product. If they didn't make that clear, people would be complaining to them that it didn't work. If you have very resistant or virgin hair it's probably necessary to use such a high temp. However, if you know what you're doing or what works for your hair type you can easy do a few things to retain more curl. For one, skip all of the blow drying. Apply it to air dried curly hair, and just let it dry before applying the flat iron. Then, use a lower temp and maybe less strokes with the flat iron. My stylist suggested that regime to me as she uses keratin but does it in a way that she still has curly hair.
I followed the directions to test the full potential of the product. Although I'm happy with my results, I'm looking forward to my next application where I may experiment with a lower temp to keep some waves in my hair. It's still totally straight right now so I'll update in a few weeks if my curls start to come back.