I was thinking about timeline events are separate from the timeline,
i was trying to make new timeline with weight 0 just to make it 100 when needed to use the event.

i thought about 2 solutions that might work.

-Maybe coupling event probability with timeline weight could work.

-Being able to add the probability to the timeline. Add value "0" to main timeline and "100" to the timeline that has the event. Then it wouldn't work until the timeline is back at 100 weight

Second option has more possibilities coming with it, but i don't really know how hard it would be.