If you are going to splice those hoses, use a metal connector that is
barbed. Once, I inserted a long threaded bolt in the end of a a/c hose.
Dont remember why,but I added freon,and did a leak check with an electronic
tester.. The freon acutally leaked out the end of the hose with the long
set of threads. Maybe 1.5 inches of threads,screwed in,and clamped super
tight.A  non threaded bolt shank that was clamped, did notleak. This is why
I say use a barbed fitting.I think that the barbed fitting is all that is
abvaliable, anyway. The early vanagons used this where the large nuts
attach to the rear of the compressor. The other end of that  piece of metal
is barbed.

A/c hoses are super cheap.Sometimes 2 or 3 hundred for the complete 55 ft.I
think you can go to a place that makes up hydraulic hoses.I would make them
all a couple of inches longer that the origionals. If you have the money
and a nice vanagon, go ahead and get the new hoses.

Used a/c hoses that once had r12 in them, act as barrier hoses. The oil
that is left inside , blocks most of the 134a from excaping. Still, they
are old and 134a uses pressures that are about 20 percent higher ,than for
r12.Only occasionally have I heard of one blowing.

Personally, I would reuse the hoses, and make the splice.I think Maggie Dew
did the exact same thing as you , in her subie vanagon.Look up her
experiences in the archives.