Using a search engine, as I haven't heard of this brand before, I see it is nascent iodine. So, from my limited knowledge, then:
1. You don't have to take it on an empty stomach, but you will gain more benefits from the straight Iodine if you do.
2. According to the website promoting Detoxidine, there are 1950 mcg of Iodine "as nascent iodine".
3. This is a personal decision on your part. Educate yourself more on Iodine before you start increasing it. There's LOTS of information on this site. Look for the recommended readings. This site started way back in 2007! I am in awe.