I want to finalize my Pi project and am concerned about the wire and connectors, gauge, durability, connection. Do you think that I can use the standard pi jumper connectors as a permanent solution or is there a better "production" type connector?
You don't give enough information about what you are connecting to answer.
I would use an IDC connector (possibly paired with coloured ribbon cable) for the Pi end. These are used inside PCs to connect peripherals, so should be reliable.
I would solder the other ends to the circuitry at the other end, but this depends on what you are using.
I use a number of 2,3,4 & 6 pin connectors to make patch cords. These can often be scrounged from old computers.
The gauge is obviously fine for anything running off the pi at a distance of 8". The durability is also fine, considering the pi itself is kinda delicate and you haven't said anything special about the circumstances. The casing is reasonably thick and doesn't split or crack unless cut. You can tear them apart without accidentally exposing any metal.
Those are stranded aluminum and pretty easy to strip with an exacto knife if you want to solder them on at one end. The only thing about them vs. a cable is it gets tedious pushing them individually onto the pi pins if you are going to plug and unplug whatever regularly. However, the square connectors are the right dimensions to tape/glue together if you are connecting to a bunch of adjacent pins.