Could you please help me with the fit for this Vanson jacket? I'm 5'9" / 137 lbs and the jacket is size 36. The jacket looks a bit loose from the back and slightly long, to my eyes. This would be for non-riding use. The jacket was ordered from Thurston Bros and they have offered to exchange to another one. Shall I go down to size 34 and shorten the body and sleeve length (1/2 to 1 inch)? Would very much appreciate your feedback. Thank you!