I am not quite as tall as you (5'10") and a little younger (30) but am fairly big boned and broad shouldered. I have set my target weight at 175 for now. Once I get to that point I will see where I am at and will adjust accordingly. I know I could probably go lower but I may decide to do some weight lifting which would increase my goal weight.

Why you decide you want your goal weight to be is really something that you need to decide on as it really does depend on your body type. You have a first goal of 225. Set a second goal at 200. When you reach that you will have a much better idea of where you want to finally end up. Ultimately though, weight is just a number. Feeling fit and happy and energized is what really matters.