Those tabs look fine to me.
If you're using a capo on the 4th fret and your guitar is in tune, I don't see how it could be coming out "too low", unless by too "low" you mean too "bass-y", as opposed to the actual notes being wrong. I think that's probably what you mean, in which case you can correct the sound (crudely) using your amp's EQ. Turn the bass down and the treble up. For example, if your bass and treble are both on 5 at the moment, try reducing the bass to 2 and increasing the treble to 7 or 8. You should notice a sharp differnce in tone. Apart from the fact that Lindsey is playing a very different guitar from you and his is going through a Roland synth module, his guitar also has an "individual string volume" control, which means it will be practically impossible for you to achieve an identical tone.
The "finger scratching problem". I can only guess that you're having this problem because at least part of your nail is coming into contact with those strings. You should try to play the A and E strings with only the "flesh" of your thumb, not the nail. Playing them with the nail makes it sound far too treble-y and they will start to drown out the melody notes. Remember, this is Travis picking at its finest: you have two VERY independent bass and melody sections going on at the same time, and those notes on the A and E strings are supporting bass notes and should underlie the melody notes of the other four strings. You should play the bass line of the entire song by moving your whole HAND up and down while your thumb is in a pretty much fixed position. The four fingers should move, NOT the thumb. (Watch the Dance video if you're unsure about this.) If you try to play the bass line by moving your thumb up and down, you'll never get the rhythm of the song right and it will sound jerky.
Hope this helps ya out!
