I've made 4 or 5 orders over the past few years (both small and large $), and I'm yet to get dinged. I'm sure my luck will run out eventually, but the fact that they use USPS rather than various couriers really helps your odds.
After going back and forth with Luxire, it was pointed out to me that they measure sleeve width differently than most MTM manufacturers - they measure at the armhole rather than across the bicep. I'm not sure how they then determine how to taper the arm toward the cuff, but in my case it resulted in a literally skin tight sleeve and the tightness across the back you describe. I have OTR shirts with sleeves that are too long/too short, but none of them exhibit this issue,...
The point where they are too tapered is when they can't fall cleanly over your shoe, which is why a lot of people aim for 2/3 of their foot length. These pants are also too tight elsewhere, as evidenced by the pulling/lines.
Very nice. Can you elaborate on which collar you used and what changes you made? My favourite collar is on an old Borrelli that I was going to send in for replication (wide spread, 3.5" collar points).
More than just seweing on a pair of buttons - if you can't find matching buttons, you would be looking at replacing an entire set. At that price point you would do better for your money at Suit Supply.
My preference is for shirts to hang clean and flat, rather than shaped at the back. I have a rather big drop, so I require a steady taper to tuck cleanly without pulling elsewhere. I suppose it would be a consideration to neutralize a particularly voluminous shirt, though.
Although that stands to reason, perhaps it ultimately depends on how much correction is required. My darts are quite linear as opposed to curved - I don't reckon my tailor is giving much consideration to the Z-axis when he creates them. This is enough to eliminate billowing for me, but I could see how it may not for someone with a very hollow lower back, or a very curved spine, or a desire for a tight fit.