It's a little eerie but I bought this a day before his passing. Despite the current Kiesel deal, Holdsworth did play an Ibanez & had an endorsement deal which lasted for two years.
One of my favourite Allan Holdsworth video is this one captured live in 1974. He played a Gibson SG & it's simply amazing how the volume induced drive gave him adequate gain for the job; we know there's no distortion pedal going back then so players have to crank it way up to get the drive going. Watch how he retuned one of the strings during play like it's nothing. Also, most of the time, he wasn't looking at what he's playing; it's already embedded in his mind, he just manifested it there & then. 👍