Quote: "best thing to do I would say is when the musics done is ask the owner if they are satified its different enough "
They would just say no its not,and try to squeeze some bucks out of you,chances are they used a riff or chord structure borrowed from somewhere themselves,lets not forget a lot can be coincidental.
Your statement about recording it yourself is actually quite valid I was merely nitpicking the principle of using some elses complete work,in music its very difficult to prove much unless you admit you took it from someone else.
If its not your intention to directly rip off an artist then its very unlikely they will come after you unless you start making a lot of money and they think they can prove it beyond doubt.
Using something directly off a recording is easily proven.