With respect, get some instruction/experience somewhere, you're obviously keen and a go'er but it might save your life.
From the stump it appears the tree sat on the bar and you had to get a wedge in there to free it ?
The front cut is nearly right thru' the tree, that isn't the best way to be honest.
Read up on the falling threads here, you'll see 30 - 40% of diameter mentioned regularly.