Vote Count line indicates number of candidates.

[beausmith]

Another feature which doesn't solve this but helps, is to update the "Vote for N." line could be updated to include the total number of candidates (when there are more than X candidates?)…

Vote for 1 of 13 candidates.

And after you select one choice…

Vote for 1 of 13 candidates. You have selected 1.

When selecting multiple the "vote for" line could display…

Vote for 3 of 13 candidates.

And as you select candidates…

Vote for 3 of 13 candidates. You may select 2 more.
Vote for 3 of 13 candidates. You may select 1 more.
Vote for 3 of 13 candidates. You have selected 3.