So for example, someone with 518 earned merits would get up to 2 votes in the 250-merit criteria and up to 51 votes in the 10-merit criteria, if I'm getting this right.
Someone with 72 earned merits gets up to 7 votes in the 10-merit criteria and obviously none in the 250.
Right. Also, for these calculations you're not counted as trusting someone if the merit they've given you puts you below the 10- or 250-merit threshold.
The 250-merit thing happens at the very end (after the 10-merit one) when there are only about 50 people in consideration (currently), so 2 votes is not insubstantial there, and you're not that likely to actually be limited.
I assume both can be used in full, i.e. using the 250-votes doesn't reduce the number of available 10-votes (or maybe I should call them "ballots" to not confuse with the person getting the votes).
Right.