There is something wrong with kidnap. In this instance I spent over 1000 ducats to have those plotters join and have 383% plot power. Out of my 5 tries, none worked.
In another trial against a lowborn courtier(an adult), I had 200 plot power and 5 backers. I was unable to kidnap her for 20 years until my character died.
From my experience, kidnap plot(which seem to be have been recoded in a recent version) is either impossible or has an unreasonably low chance of succeeding..
Looking the code(there are more than one copy of the following in the file):
plot_target_char = {
is_adult = yes <- should be deleted
NOT = { trait = incapable } <- should be deleted
prisoner = no
}
Because of this, children and the incapable cannot be kidnapped. But they can be the target of kidnap which results in kidnapping plot not succeeding forever. They shouldn't be protected.
I've done a rough calculation on the plot chance, too.
With the best possible condition of one person having over 90% plot power contribution and over 300% plot power overall, MTTT is 40 months in one of the two kidnap plots. With both methods, MTTT is 20 month for that plot backer.
If the target's spymaster with high intrigue is helping you(over 90% plot contribution) and you have over 300% plot power compared to the target, it means the plotter is infinitely superior in available resource and cunning. I believe it shouldn't take 2 years to kidnap the target as the plot will be discovered before that. More plotters will decrease MTTT, but it will also increase the chance of discovery, too. Since discovered kidnapping plot results in a dishonorable trait, maybe the chance should be upped a little?