I think you have a nice, manly tone. It sounds good to me.
As you say, bringing this tone to the high notes makes this song more challenging, so you usually use falsetto at the top. I think some of the difficulty of the top notes is because the tone is losing some "clearness" around middle C (For example at :34 "and sit" at :57 "seas" you are medium intensity near middle C and raspy, but as you continue lower in pitch and intensity, you sound very smooth).
If you were to clear bring a soft but clear tone to that area in practice, then work on making it connected, that may give you more release.
Nice job on a difficult song.