25 lbs of Flaked/malted corn

[Rclark12]

So a local brewshop sells a 25 lb bag of flaked/malted corn for 39 bucks. I've ran one all grain and it was only a 5 gallon mash but now Im getting a 55 gallon drum and would like to tackle a larger all grain, or maybe just adding a little sugar. I've been reading into other peoples all corn ag's but haven't seen much questions about bigger mashes getting answered.
Id love to make an all corn but I always read flaked corn is only efficent enough to convert itself. I used roughly the 2 lbs to a gallon method on my first ag and it went well but getting the beer out of all the grain was hell, I think Id like to do more like a 1.5 lbs to a gallon, or as I mentioned maybe do something like less then 1.5 lbs of grain per gallon + a little white sugar. My question is how much cracked corn could I add to 25 lbs of flake, at what amount of water to be most efficent. I know these are some noobie type questions but I simply was not sure if ratios change at all when doing a large mash (25-50 gallons) compared to a 5 gallon
Thanks guys
any all grain or semi all grain info for a 25-50 gallon would be awesome Id really love to give this a shot