Cliffs of Dover.
Worked it for 6 to 8 months.
Final result: I could play it at 95% (-ish, depending on the day) of the original recorded tempo, with no obvious errors, IF, and ONLY IF, I rewrote a couple of the most-difficult riffs in such a way as to have roughly the same notes, but played using a slightly different technique.
Only in the last few years did Troy Grady et alia help me realize that I'm a natural downstroke-escape (or "upward pickslant") player whereas Eric Johnson and a lot of other folks are the opposite. So there were some riffs in the song that I could just not get past 70% of the recorded tempo no matter what I did, especially if I started them with a downstroke. But if I started with an upstroke and judicially introduced some pull-offs or string-changes-via-sweeping, it became manageable.
Since I'm still not reliable to avoid noticeable errors when playing at 100% of the original recorded tempo, I guess I'm still working on it.
And my standard for live performance is to be able to rehearse it at 105% of the original recorded tempo, a few times back-to-back, without any terribly-obvious missed notes. I frankly have given up hope of that ever happening.