I tried - I really did. This was like the 5th try, and every time I got to the chorus, I started speeding up.
So I just listened to the rhythm in my head, started the strum, and took it from there.
If I could do it with someone who could sing, rather than doing the singing myself, I think I could play it slower. Or if I could actually figure out what the tempo should be, figure out how to use that damned metronome, and put the two together...