Are you sure the shoulders will not fit if you go down? I think the front pic looks like it was taken with the camera angled downward so that accentuates the issues I see.
Overall, the jacket just looks too large. The pic from the back is better however. Still, jacket is long even for a classic length, I just do not think the proportion is good for you.
And I don't know if there has been a discussion by some of the resident experts of where the shoulder seam should sit, especially on someone with large shoulders. Not wide but large balls for the socket. Muscular, cannonballs whatever you want to call it. There can be such a difference as to the end of the acromion compared to the end of the 'shoulder' depending on build.
For someone with wide, developed shoulders, especially if your hips are not super wide(one can have an athletic V shape either way but some are more straight down, others former another angle) and your thighs not massive and wide, you don't want to create the illusion of widening the line across the top of the jacket. I think the shoulder seam should go more across the acromion(look that up,easier than my idiot self explaining) and not the 'end' of the shoulder. Yes, there is the question of where is the 'end' given shoulder are often rounding and not a cliff.
Anyway, I have gone on too long to say that the jacket looks too wide at the top line, too big in the chest and too long. I could add still too big in the waist. From the backside, much better, probably less of the same. A more perpendicular sleevehead attachment making the shoulder seam spread narrower more at the top than at the bottom of armhole.
Maybe if you have a picture without the jacket just to judge body type(I won't ask for your portfolio shirtless or nudes) and I could see if I believe you or myself more about the shoulders.
Hey gambit50, thanks for the response. You're right about the fisrt pic, I did noticed that. I have tried to go down and my delts pop out of the sleeve. Plus I don't have the chest to use a 44, but a 42 is too tight, since it measures 42.5". Problem is the shoulders, they are shifted foward, plus a bit of muscle and some large shoulders blades, expand the chest area of a 42 jacket and cause shoulder divots. That's why I'm asking if the chest can be shortened a little bit.
I looked for the what is the "acromion" and well, I will try to get a pic later of the size I used before (a 40) and the seam sits right there, at the acromion, and looks awful. I got a bespoke jacket and the measurement between the shoulder seams is 19" this one have 19.25" so it's not a huge difference. About the lenght, yes I think it's a bit too large but the regular, the button stance it's way high, and I don't like how it looks, plus jacket doesn't cover my butt. The jacket have 33" long, 32" would be perfect or 32.5" but I don't know if that can be fixed.
About the shirt, I understand, don't worry, I have this one of some I bought RTW, they weren't ironed yet nor washed. I just got the package that day and had to try them on. This have 19" across the shoulder seams and 45" chest. I can't go a size up, cause I use a 16" neck.
Shirt fit. (Click to show)