They say you can feather edge self leveler and it is possible, but if you have a big pour in lots of areas you usually get a small ridge at the end, unless you have help.
I have a 5 foot screed trowel I use in combination with a 16" trowel and those work well to get the stuff where it is needed.
When it is dry I take a scraper to eliminate any dried lumps that are sticking up and use a bit more of the self leveler mixed thicker to finish the edges using a 16"trowel
If the edge is less than 1/4 inch I just use a bit of thinset to feather the edges.
I also prime the top of the self leveler before going over it with tile.
As the name implies it levels out the floor getting rid of hollows and dips and other low spots so you have a smooth and level substrate to tile which makes your job go smoothly.
Make sure you prime before pouring any self leveler.
Here is Mapei's site that has info:
mapei.ca