In the updated OP it now says 1000XC is the requirement for trustless mixing all the time. Is this final?
1000 XC for xnode do make sense because you will earn XC if run as a xnode.
Yup, it's 1000 XC.
This amount is still somewhat provisional.
Also, if XC's value increases, it's very likely that the required balance will decrease.
but why decrease the needed amount?
i think 1000 is a good amount and the number of needed coins should be fixed and not changed. i mean what happens when the price increases -> the number of needed coins is decreased.
but what happens when the price drops afterwards? will you increase the amount again? i think setting the number to a fixed value is the best solution and won't lead to confused users
Changes would not be made often. It would need to increase, say, 20 times its current value before we'd change it.