Hello Group!

After retrofitting the factory ´87 tintop A/C in my ´92 Vanagon in 2004,
it seems it finally needs new hoses.
Refrigerant keeps disappearing quicker and quicker...

I re-used the stock ´87 hoses back then, and also the R12 expansion
valve (working with R134a since the retrofit).
For several reasons, I need to drop the evaporator anyway, so I think
this is my best chance to replace all the old stuff including the
expansion valve.

Does anyone have the information about hose lengths, position of
pressure sensors etc on paper?
I want to get some quotes from hose suppliers, but don´t want to pull my
hoses out upfront, just to learn it´s too expensive.

I would prefer the later style hoses, with the trinary pressure switch
instead the separate hi/low switches.
I like to check the A/C myself as much as possible, and might need to
remove the switch without losing refrigerant.

Thanks for any help,
I am struggling to get this information in Germany, as A/C are rare and
servicing extremely expensive.
A/C shops keep selling their services as some kind of magic still...

History:
In 2009, got the system filled by a shop, nice cooling effect.
In 2014, system didn´t cool well, I added R134a via Walmart-style
re-fill kit (12oz can and gauge).
In 2016, system cooled okay´ish in the beginning, but faded quickly in
the summer, now not even activating the compressor.
Bridged the low pressure switch, compressor kicked in, but no effective
cooling after a few minutes idling. No green leak detection fluid can be
seen (only visual check at accessible areas without U/V light, no check
in evap housing or detailed condenser check).

Regards
Raimund