Here's the info I had collected in my Sig Cane book research:
His signature cane consists of the initials ‚ÄúJA‚ÄĚ. While at Perthshire, he became the first artist to include his personal signature cane in a Perthshire Paperweights weight. Allan made a filigree crown paperweight in 1971 for Perthshire, which incorporated his signature cane embedded in the bottom. Figure Allan-0 documents the Perthshire cane which is predominantly green. Figure Jack Allan-1 contains a yellow/orange color which was used after 1963 and probably before 1971 in his personal weights, based on a comparison of the technical merit of the weights in which it is found. Dave Moir reported that these orange canes were made in 1963 and 1964 at the old Vasart glassworks at Perth when Vincent Ysart was absent. After Salvador Ysart died, and business was tough, a glazier friend of Augustine Ysart supplied them with cut-off bits from Viltrolite tiles. The tile pieces were melted and used for making millefiori canes. Jack Allan-1 is made of those Vitrolite canes.
UK collectors have reported a third variety of cane used at Oban: white letters in a dark field with 25 millefiori florets around the outside. [Jack Allan-3; and Jack Allan-4] Signed weights were also made while he was at Strathearn [Jack Allan-5], and perhaps Vasart. Richard More, an authority on Strathearn paperweights, has reported:
‚ÄúJack did indeed start at Vasart in 1948 at the age of 16 but he was an apprentice to all three of the Ysarts not specifically just Salvador. In 1953 at 21 Jack went away for his National Service duty and didn't return until sometime in 1955, by this time Dave Moir was also a new apprentice hired in 1954 at age 15. No one but the Ysarts were allowed to make paperweights and no one was allowed to use personal signature canes except for the Ysarts. After Salvador died in 1955 and Auggy in 1956 things became very tough at Vasart financially and a local glazier used to give Auggy and later Vincent his leftover colored cut pieces of Vitrolite which Vincent used to make canes and glassware decorative colors. According to Dave Moir it was in late 1963 or early 1964 at the old Perth Vasart works that he and Jack made Jack a few JA signature canes out of this Vitrolite glass while Vincent was out sick one day. [ie figure Jack Allan-1] According to Dave, Vincent frowned on anyone making friggers on their off time and when Vincent went home for lunch or dinner so did everyone else. Most JA canes were used by Jack after Vincent left Strathearn in 1965 and most likely between 1965 and May of 1968 when Jack left with Stuart Drysdale to form Perthshire Paperweights, or early on at Perthshire as Jack had a lot more leeway there to experiment on his own. Early JA weights may have both Vasart and Czechoslovakian canes in them as Jack, Dave and Auggy used to go out to lunch and beer with Frank Eisner and Jack could have gotten some of these canes from Frank. Regardless, JA signature cane weights are very rare and highly collectable.‚ÄĚ
See the section for Caithness Glass about a rare ‚ÄúOG/JA‚ÄĚcane.