Motorcycle jackets sizing, too tight or too loose is better?

I have an athletic build, which makes shopping for clothes in general a nightmare. I've been shopping for jackets and I finally decided on the Merlin Perton but I have a slight issue.The common knowledge is to size down on the brand as they tend to run a bit larger, however I when went with a Medium, the arm holes and shoulders were way too tight and I could feel the fabric pulling into my shoulders/chest if I raised my arms even just to 30 degrees. The sleeves and waist was a decent fit however, still a tad baggy but it worked. I decided to size up back to a Large in hopes that the shoulder area/chest would have enough space, but the sleeves and waist area are pretty baggy, allowing the elbow pads to rotate a bit. They move just enough that the pads shift towards the ground, exposing the 10 o clock for L and 2 o o clock for R positions on either side. Most of the elbow is still covered, and if I curl in or lower my arms it tends to shift back to the fully covered position.But should I consider going back down to the Medium? I don't know if I could actually stand the constant pressure, especially since I am actually working towards increasing the mass around the area. I'm just worried the sleeves are too loose around the elbow and of course it is less flattering around the waistline, giving me an overall boxy look.Any tips for keeping the pads where they are? The jacket does have a water proof membrane so I'm worried that any aftermarket stitching or something would ruin the lining. via /r/motorcycles https://www.reddit.com/r/motorcycles/comments/euy35h/motorcycle_jackets_sizing_too_tight_or_too_loose/?utm_source=ifttt