on mine i can have a little fire of about 1/2" which will remain at the front of the grate where just over the radius of the grate. as i increase the feed rate the fire will get longer and if the feed rate is continously increased it will eventually fall off the rear while not being completely burned up. this you dont want to do because you will burn the grates and waste coal.
when running manually with the thermostat jumped out to run continously you can play with the stroke adjustment and see what a full turn will make in the appearence of the fire and how long it got from the previous setting. this i had to do for a year before i hooked up the thremostat. i had times where i was roasting and times where the house was chilly. by operating like this for a year i was able to see at what the results were by changing the stroke adjustment up one or back one turn.
what i had to learn after hooking up the thermostat was at what stroke setting was the best for me. if set too slow at time when the thermostat was satified the fire would just about go out. if set too high i was just wasting coal. i had to find a happy medium to cover both outcomes. when i lite mine (next week) i set it up so that the fire is just less than half of the length of the grate and leave it. as the outside temps start to really drop the feed rate i have is not enough to keep me warm and then i turn it up one turn and leave it that way until the cold snap is over. i actually have it down to the point where i use half turns for the feed rate.
if you want to venture with it run it manually for about a week and note the changes in the fire position to relationship in the feed stroke adjustment, i garrentee when you put it back on the thermostat you will know where to set it and how long the fire will be to keep you warm
one other thing i had to do was to keep track of how many turns gave me the desired results