Looking for advice rigging full body misc. items.

Bearplane

Im currently working on a set of shirt type misc items, one for each class. I can model them fine but when it comes to rigging i just cant get everything to flex right, especially the sleeves. My process has been this:

1. import two meshes rigged and unrigged
2. delete the unrigged mesh except for the faces that the shirt will cover
3. expand from this base to create model
4. skin model to skeleton
5. transfer skin weights from pre-rigged model to item model
6. export new model and skeleton

This works for the most part, certainly better than painting all the weights from scratch, but its far from perfect. Theres a good amount of tearing and stretching that im having a really hard time getting rid of. sometimes fixing one area breaks another, and some problems appear nearly impossible to fix. Is there something i can do to make this process go any smoother or is weight painting just the bane of every 3d artists existence?

TL;DR what is the most efficient and accurate way to skin a misc item to a character model?

EmAr

Which models are you transferring the weights from? If you are having problems with the SDK source files, try decompiling actual game models. There are some differences between game models and sdk source files at least around Pyro's neck.

Bearplane

Im transferring from the ones in the polycount tf2 resource pack. I tried working with decompiled models but they didnt have any weights at all. im not sure where the resource pack ones are from.