It could be a hard one to find out 100% as we know he experimented with his sound all the time. We had a discussion about the different echoe units he used and tested. These being used for his tone as well as effects. He then seemed to stop using them later on in his career. It could be a mixture of things from amp settings to effects, graphic equaliser settings who knows. We could be guessing to the answer we may find out more about RR sound when we hear what Pete Merton's has to offer in the documentary. Good luck with your search
I think he might have been using the modded channel on this tour which could explain why the soundman was adding echo and chorus. Could possibly be a combination of the amp mod gain, the Dist +, and the 10 band. . The chorus added to Randy`s sound somehow didnt make it sound soft on the hi gain tones like chorus can do. Very unique.
That could very well be it. He had so much distortion/gain coming out of that amp on the Diary tour as compared to Blizzard tour. Running delay and chorus through all that distortion in the guitar line wouldn't have sounded too hot - no effects loop back then. I think we're on the path to figuring this out!