I am a hardwood flooring contractor. I have some knowledge in setting tile but have only done so in my own home. I have realized this morning that I know a lot less than I thought. I have agreed to help an old friend tile the sun room at his home. We started last week by floating the slab because it was falling about an inch away from the home. It seem to go well. Next we used a Self leveling compound and floated it out to what we thought was level. I began setting tile this morning. What a disaster. The sub floor has so many un- level areas that many tiles are simply rocking back and forth and not adhering at all. I plan to return in the morning and remove the tiles laid and scrape up the thin set. Start over. What is the best way for me to get this level. my friend is not expecting perfection but there has to be a better way. I'm sure I am way off base with my approach but any advise would be so appreciated.