personally i take the recomended amount of food for the day, put it in the bowl and let vixie freefeed. she eats as much as she wants when she wants while still getting the recomended amount for the day.
ive Always free fed, and as much as many times ive been told oh thats how you get fat dogs...*rolls eyes* in 20 years myself nor my family have ever had an overweight dog, my grandfather who used to breed freefed and never had overweight dogs...and it works best for us and our dogs...
however it isnt for everyone.
however at 6months if you dont want to leave the food down id prolly say twice a day now....