While I have no information as to the LPM resolution of papers, I have always heard that the enlarging paper is not the weak link in the chain. I imagine that this is due to the enlarged image degrading through enlargement far more then the limitations of the paper resolution.
This subject of paper resolution comes up from time to time.
If it were me and I was wanting to extract the greatest resolution from my materials and equipment, I would work on the following:
1. Limiting the effects of possible camera movement
2. Achieving accurate focus
3. Limit the possible effects of lens defraction at both the taking and enlarging lens stage. This means not stopping the lens down beyond a certain point if possible. For me on 4X5 that amounts to no more then F32... preferably F11 - F22. In 8X10 that amounts to F45. In 12X20 that amounts to F64 on the taking lens. If enlarging I try to work 2 stops down from wide open.(F11-F16)
5. Choice of film, film developer, and processing procedures.
These will all make a noticeable difference in resolution. This process is truely a chain and it is no stronger then the weakest link.