Cotton-wrapped poly is the worst of both worlds. Some brands are better than others. Check it for slubs, then pull gently to check how rubbery. The more give, the more problems it will cause. If you must choose between exact color match and good quality, go for the good quality.
Manufacturers buy in such large quantity, that they have their threads dyed to match.
Don't hold a whole spool against your fabric, instead, unwind a single strand to check color. Never use polyester on silk because it is 4 to 7 times stronger and will distort the seams. Use fine cotton thread instead. Silk thread was created for hand sewing and is not suggested for machine use. Don't use silk thread on silk fabric seams, it is way too strong for fine silks and for most wovens.