I recently got a TM Lewin slim-fit shirt. It's a 15.5 neck, and I had them alter the sleeves to 35. The fit is great for the most part, but here's where I need help. At times, the sleeves feel a bit short. If I am standing with my arms at my sides, the shirt is fine. But when I am driving or moving very much, the sleeves seem to ride up a bit and feel a tad short. I believe this has to do with my back and shoulders more than anything. I am ordering some more shirts and want to make sure I get the size right. I think a 35.5 sleeve would do better, but I am worried that it might have too much material when in a relaxed position, or just be too long in general. Thoughts?