Limit how many votes a Reviewer can cast

Just like on the Ideas portal I can control how many votes a user gets, I want to control how many votes a Reviewer can cast.

I want to expand access to Private comments, which requires Reviewer permissions, which in turn grants unlimited votes; and this defeats the vote limits I have on the portals.

If this is too complex, I could live with just a knob for 0/unlimited, forcing votes to happen on the portal when set to 0.