Power steering line on the rack

That's the wrong approach. Replacement hoses are ordered by application, meaning model, year, and engine size. Other than that, there aren't different sizes.

If you need one of the steel lines on the rack assembly itself, those are normally not available separately, but your car is one of the exceptions. We still don't need to know the diameter. There's a short one and a long one listed.

For most car models, the easiest way to solve this is to visit a salvage yard for the pipe. They sell usable rack and pinion assemblies to the rebuilder companies. To be reusable, they aren't going to want to take a pipe off. That would leave them with a worthless assembly. Instead, they'll look for one with a broken housing from a crash and take the pipe off that one.

You can also visit one of the pick-your-own-parts salvage yards to find the pipe you need. The better yards will have their cars solidly-supported a few feet above the ground so you can easily crawl underneath. You might also find one with the engine gone, then you can work on it from the top.