Using a 5 gallon bucket to ferment 5 gallons of ale

I just made a batch and fermented it in a 6.5 gallon bucket. I lost a little less than half a gallon to blowoff. That said it fermented around 75 degrees. I'm about to get a freezer and I have a temperature controller. So that means I can ferment from 60 to 68 degrees. Due to the lower temp can I get away with fermenting a 5 gallon batch in a 5 gallon bucket? I'll use a blow off tube. Will I lose to much wort?

I've had to clean out my airlock before when fermenting 5 gallons of ale in a 6.5 gallon bucket at 62F. All ferms. are different. Probably the only safe way to do that is by using Fermcap to control the foam. Even then you're still likely to have a mess. Whenever I want to brew and have my 6.5gal. bucket full, I will rack it to a 5gal bucket (secondary) after a week or so and free up my big bucket for another brew.Most of the time I rack my new brew on top of my other yeast cake and save on having to buy yeast.

Using a 5 gallon primary for a 5 gallon batch will most likely end in a mess. The 5 gallon would work well for a secondary (assuming you only move the beer in there once fermentation was absolute complete,) and the 6.5 should remain as your primary.

Cooler temperatures can help, I personally tend to ferment on the cool side and haven't had any blowoffs in the 6.5 gal. bucket.

Ive fermented 5g of beer in a 5g carboy without any problems in the past, however, you absolutely must use a blow-off, and also I would suggest keeping a close eye in it the first few days, just in case.