Wanneer u een PCB wilt maken, welke informatie moet worden verstrekt aan de PCB-fabrikant?

I’m designing a new PCB where I have a whack of connectors that have to line up with the metalwork. There are some problematic connectors. All 4 pins are round. I want to have the holes as small as possible while allowing for good solder adhesion over the full length of the pin. I’m looking for guidance on how much clearance around the component lead I should have in order to get good solder wetting and adhesion.

While bored recently, I decided to take apart a few old pieces of electronic equipment and attempt to reverse-engineer them. I’ve been doing pretty well, but I’ve come to an IC that I can identify but doesn’t seem to exist on the manufacturer’s website.