In 1989 he guested together with Dee Dee Bridgewater, performing Precious Thing:
I assume that it was during this same show that Ray and Dee Dee also performed O Sole Mio - see the two tiny fragments at 1:00 and at 2:00 in this clip:
[Clip was removed from YouTube]
Ray performance at the 1990 edition (held from 28 February to 3 March), doing Good Love Gone Bad (Gli Amori in Toto Cutugno's original) was a triumph.
Good Love Gone Bad (first performance 1990):
Good Love Gone Bad (second performance 1990):
Gli Amori (Toto Cutugno 1990):
This clipping from Jet magazine (13 March 1995) shows that Ray came back to Sanremo in 1995. He performed Angelina on February 21.
In this show Ray also assisted guitarist Alex Britti in a performance of Volare (Nel Blù Dipinto Di Blù), the 'anthem' of the festival (cf. this):