This isn't a problem I have with one of my French cars, it's my old P38 Range Rover but there's a huge number of knowledgable people on here so I thought I'd ask

Last year I fitted a new condenser and drier and had the air conditioning recharged. It held a perfect vacuum test when it was on the machine and the engineer even commented that it was unusual for a car of that age to hold such a good result on the vacuum test.
Unfortunately, my joy was short lived as when I got home I was checking something under the bonnet and I could hear a hissing noise. One of the aluminium pipes that run along the bulkhead has a pinhole in it and it was leaking refrigerant. I've replaced all 4 of the aluminium pipes under the bonnet but am worried about getting it recharged again.
The cost of recharging it has increased significantly recently due to a huge increase in the cost of the gas and as the Range Rover holds 1.5kg of gas the cost of a recharge isn't insignificant these days as well as the environmental impact of leaking the gas straight back out!
This got me thinking... I have a huge nitrogen cylinder in the back of the workshop that I use for recharging the Citroen spheres. I was wondering about filling the system using a charging rig that's available online to connect the Nitrogen cylinder to the filling ports. At least that way I can leave the pressure gauge on it for a week to check for any leaks before having it recharged.
If I can get a set of gauges, does anybody know what pressure to fill the system to? I don't want to dump to much in and find it blows a hole in the new condenser.
Any thoughts/suggestions would be much appreciated.
Thanks,
David.