Pin stripe jacket pattern matching

Bad idea to match the stripes unless you have a perfectly square shoulder angle. The back shoulder width should be cut (in bespoke) between 1/2" and 3/4" wider than the the front shoulder. The excess fabric is eased on and helps create room over the shoulder blades and stops the front shoulder from creasing.

This is something I'm actually curious to hear thoughts about too - one expects to see excellent matching on high-quality garments, but occasionally a really obviously odd mismatch occurs, or there's slight oddities, and it's hard to tell when these might be oddities of the construction or mistakes, which do happen even on high-end stuff. Can't expect perfection, after all... and sometimes it's downright interesting.

More broadly, matching importance of other patterns beyond just pinstripes.

I think they can generally line it up, but you can't expect matching for what Len just said. The pieces of cloth are of difference size, angle, etc.

Len is right that you should not expect the stripes to match at the shoulder seam. Lapels should obviously by symmetrical, ideally with the stripe following the curve of the edge of the lapel and not drifting off the edge. Pocket welts can be made to match if the pockets are straight; some tailors prefer to cut them with the stripe running along the length rather than the vertically. If they are hacking pockets, then the stripes would usually not match, as this would require cutting the length of the pocket on the bias, which could cause the pocket opening to sag with use.

Any horizontal striped in the pattern should match between the body and the sleeve. Ideally vertical seams (such as the front dart and the center back) should fall inbetween stripes so as not to swallow them, although some Italian tailors seem to like to swallow a stripe in the breast dart (there's a thread about that somewhere).

The fabric is never cut at an angle; this would mean cutting on a slight bias which would affect the drape of the coat. The front dart is usually, on striped fabrics at least, kept along the straight so that it runs parallel to the stripes.

The top-collar will usually be matched to the body at center back, it is not always possible to match the collar ends with the lapel stripes.

the secret is - never force the fabric to go where it does not want to. Force it, and you can in order to make the stripes match on the shoulders and from collar to lapel, and it will come back eventually and nip you in the rear end.

I'm guessing that fabric is woven with a diagonal stripe? In which case all bets are off.