proper use of air shocks
I used air shocks for years when I had a boat. I even had them on my 68 barracuda back in the day. Never had an issue. However, the metal was about 40 years newer on the car back then. I think “never” is pretty extreme.
Loading the upper shock mount can be a concern. However, they are loaded every time you drive it & hit a bump. If the upper shock mounts aren’t bent or loose, you will probably be ok for awhile.
‘They used to sell leaf spring helpers back in the day that bolted on to the existing leafs and performed the same function. Would think they are cheaper than air shocks.