It may seem crazy that I reply after such a long time, but I was recently thinking about a related issue. Have you been stuck at 120 for a while? If so it is unlikely you will overcome this by simple repetition, and it is worth analyzing if the movements you are using are actually capable of 160bpm - it doesn’t matter if it comes out super sloppy, but are you already capable of that speed in principle - for example in one of the sub-licks that make up the solo?
PS: luckily I think the speed of the recording is more like 156bpm, so just a tiny bit more doable by humans When examining some live recordings I noticed they may even slow it down a bit - like 150bpm or so.
PPS: As for me, I can hit the song’s tempo all-picked on a good day, but it never feels relaxed/controlled enough and as a result I don’t think it sounds that good. With the “Andy James” method (one pulloff) I feel that I’ll soon be able to reach the right balance of speed + relaxation. Maybe I’ll eventually post a comparison video here if it can be of interest.