The biggest red i have seen have been stud stags on a deer farm i used to help out on, they were far bigger than the wild red stags i have seen but fall a long way back in size to the biggest sambar stags i have seen,we weighed a few over the years and they probably averaged 500 plus pounds but there were a couple that taking everything into consideration that would have gone over the 700 pound mark and boy are they big when you have to get them out of the bush!
Back to the original post,i still say start off smaller and grow into the bigger cals.