Sir Robin??? Are you sure about that??? Looks more like you should be called Little John being 6'4 and 375lbs.
Talk about huge!
The first suggestion I try to make to anyone wanting to develop good form is to try and imitate what a good target archer's form looks like in regards to shoulder and arm alignment and than make adjustments from there.
Find an anchor point/points that allow you to be consistant so that upon release your drawing hand moves straight back in line with the arrow if it moves at all.
My anchor points or reference points are my index finger in the corner of my mouth and my thumb behind my jaw as a secondary anchor. Having 2 reference points for your anchor helps with consistantcy.
How much the hand moves doesn't really matter. It can be a fraction of an inch or all the way to the shoulder. It can even be a dead release where the hand doesn't move at all...but with most hunting weight bows...most archers will have a dynamic follow through.
Perfect alignment of the arms creates a T image when an observer looks at you from the side.
Your shoulders should be as close to parallel as you can get them with the arrow while your drawing forearm should be in line with the arrow at full draw.
Now knowing how big you are...I'm gonna guess you have a pretty big chest that may keep you from achieving that position so you will have to make some adjustments...such as opening up your stance to help clear your chest and bow arm from the string upon release. ..which will be something you definitely need to consider with hunting clothes.
Look at Terry's form clock if you want to get a better picture of what I'm trying to describe.
Sometimes...pictures are worth a thousand words
Ray