You really don't need any more girls than LMP.
OK a 14 guy party can be a bit busy at the start until the quick-cummers start popping, but it soon thins out to 1-2-1s and in the second hour there are always girls 'on the prowl'.
Ideal for me is about 10/11/12 guys and 7 girls, which it often is as there are no-shows, guys who arrive late & leave early...plenty of room to move about and moresome action in the second hour.
Be careful what you wish for at a low ratio party, the girls have way more stamina than the guys, you will get slaughtered!!