I think the OP is asking about the illumination lights, not the warning lights? The illumination bulbs are Lucas 987, 2.2w miniature screw base with a small round globe. An Osram 3966 is a 3w version, and Phillips 12875 is a 2.4w version.
By the way, there are two wattages in the warning lights. The choke, oil pressure, brake & ignition bulbs are 3.6w, the others are 2.2w.
Yours
Vern