When I was managing my brother's body shop, I found out pretty quickly that subletting all my glass work to a mobile glass shop was the way to go. That included rebuilding window track channels, etc. It didn't take very many mistakes by ham-fisted body men that resulted in glass breakage to suck up the profit margin on a job. On any work that involved doing repairs around windows, etc. we always removed the glass instead of trying to mask around them. An unbroken layer of paint under the glass always made for a better-quality job and since we specialized in high-end vehicles like Jag, BMW, Ferrari, Mercedes, etc. the cost of doing that kind of work was not a factor. If we didn't charge outrageous prices, the snobs we worked for couldn't brag about how much their toys cost! We were more than happy to accommodate them!
Jerry