Is there an easy way to account for the number of raid members with the trinket? I would imagine there is a big delta in the trinkets value from nobody else with it to 10 raid members with it.
There is a setting on the simulator for how many people have it. The default gear strategies don’t assume anyone else has it, but you could make a custom gearing strategy with any setting you want.
You could also just simulate that trinket compared to the next best trinket with a different setting to get an idea.