Quigs: That is a cool voicing for C7! :shaka: I'm remembering that one...
RAZZLE: Judging by the version U2 does on "Rattle and Hum", from what I can tell, it's just a regular C chord there. When they play that chord on the guitar, you don't have that high "C" note like you do when you play it in standard position on a ukulele, so maybe that's why it sounds unusual to you.
Now they do add a bit of a Csus4 in there (0013). If you did that, it might help a bit. It comes in very briefly, right between beats three and four of the first measure of that chord.
Another thing is that the R&H version is actually in the key of F#, not F. It's perfectly fine to play it in the key of F, but you're a half-step lower. You might just as easily go a half-step higher, and put it in the key of G:
Hold me (G) now (C) hold me (G) now
'Til this (Em) hour (C) has gone a(D)round (Dsus4)(D)
And I'm (Bm) gone on the rising (Em) tide (C)
JJ