"Skymarker" is a British denomination. As you speak of a 100lbs bomb I understand that your intention is one of the US bombs serving as a "skymarker".
Which one is of interest for you? the 100lbs M84A1 "target indicator" ( producing a red/orange cloud in the air to indicate to bomber formation the point where they where to drop their bombs) or the 100lbs T29/ M87 smoke streamer (producing a column of smoke along its path down to earth). the first used a regular AN-M147 tiem fuse, the second a M143
As you speak of bakelite, electric balistic cap and such, this may indicate that you are speaking of the 100lbs smoke signal based on the M47 bomb, that was used in 1944-45 and not mentioned in US documentation as it was a temporary solution . It was more a "traget indicator" than a "skymarker" as it was intended to detonate at impact.
Here's a drawing of its fuze, from Henry Belot's deminest, based on a German wartime EOD's drawing from 1944:
It could also sometimes be equioped with a AN-M100 A1 fuse, modified so as to act as a "traction" fuse, so the bomb could be activated in mid air, therefore creating a "skymarker"
These are rare finds, known mainly from German late war sources.
