Timely question there Andy. When I fitted my AK rad like yours I used the same hoses and as the unions are brazed in place and not adjustable, the pipes were not the best length. I didn't cut them at the time. As you may have read on the Wales posting, one of them failed in the morning leaving 7lt of ATF on a humpback bridge. The hose had split. When we took it off (grunt, strain, swear) it was clear the the outer protective sleeve had sort of welded itself to the inner pipe. Now this wasn't a problem really but it showed that something had been going on over the years. We simply stripped it off and cut it shorter by a couple of inches and shoved it back on. Rest of the pipe looked good, but it's on the list to replace at some point. As to pipe type / quality I am not sure of the standard, but it's not very hard working pipe. I wouldn't have thought that braided stuff was really necessary. I'd guess that fuel hose would probably work. ATF isn't particularly aggressive stuff is it? What you don't want is a failure and bits going into your auto box.
I think that this could be a good candidate for preventative maintenance on all older autos really. Don't know what caused mine to fail but it wasn't rubbing. The hole was underneath the protective sleeve. I still have the bit I cut off if you need to know the bore.
Chris