For a long time, I have been making my own brake lines. I have never seen this addressed here, so I'll say a few things now.
There are are several big advantages to making your own lines, as opposed to buying made-up lines. The custom rear line that I made for the Texas Scorcher in the pic above, used uncommon 90-degree fittings on each end. You will never see a pre-made line like that. Plus, I could make the line exactly the length I wanted. Thirdly, the fittings on most pre-made lines do not swivel. This means that you may have to awkwardly twist the line to get the banjo bolt holes to orient, sometimes so much that the line becomes too short. When you make your own lines, you can get the fitting to align exactly like you want.
https://www.aliexpress.com/item/4000042761748.html?spm=a2g0s.9042311.0.0.27424c4dYHcC1o
MikesXS sells a crazy expensive DIY brake line kit. The cheap way is to buy your line and your fittings from AliExpress. That's if you can wait for the slow boat from China. Above is the cheapest PTFE, AN3 hose in a decent quantity that I have found. It is good quality.
https://www.aliexpress.com/item/4000928245969.html
Likewise, get your fittings from AliExpress, for about $5 each. Above shows just a few of the possibilities, there are more. There are several very good how-tos on how to install the fittings on the line. It is easy, although it does require a bit of care and attention to detail.
1973-1976 calipers do not use a banjo bolt fitting at the caliper. They use a flare nut fitting that the little pipe at the top of the pic screws into. You can buy made-up lines that will work, as shown above. But, your options will be very limited.
https://www.aliexpress.com/item/4000381857217.html?spm=a2g0s.9042311.0.0.19414c4dvx4nVE
Instead, if you are making your lines, you can use this flare nut fitting. A female version is also available.
Unfortunately, when the time came to make my line for the RustBucket, I did not have the flare nut fitting that I needed (I now have some on order). I wondered why couldn't you just use banjo bolt technology?
https://www.ebay.com/itm/313527310420
XS650 banjo bolts, and most other banjo bolts, are M10 X 1.25. The flare nut fittings in 1973-1976 XS650 calipers are M10 X 1.0. So, you need to buy the somewhat hard-to-find banjo bolt above.
The sealing surface on the RustBucket caliper was pretty rough and pitted as shown...
Decisions, decisions. Which sealing washer is most likely to make a seal?
I went with the rubberized washer. It works!
No alteration was made to the M10 x 1.0 banjo bolt, or to the caliper. The caliper body will still accept a flare nut fitting.