Anyone have a rough idea how many pound of trout it would take to get a gallon of oil? I have access to a lake that stocks them for clients to catch and being in Ga they don’t make it once the water warms up. I don’t want to take more than I need to but would like to give it a go to try and get at least a gallon.

LOTS. I've tried making some out of trout caught out of the lakes, and if you get them when they are just stocked they are fatter and you will get more, but still not much per pound. Under ice caught fish that were stocked the previous spring won't render you a quarter inch of oil on a gallon jar, in my experience.

2-> 2-1/2 5 gal buckets full of trout/parts will give you a good gallon of trout oil if it has rendered out well.