10GBASE-SR vs. 10GBASE-LRM + mode conditioning patch cables on old fibers (OM1/OM2)?

Hi

I have site with late 90s multimode cables where for one of the shorter runs I already have a stable 10GBASE-SR link for 4 years. Unfortunately I don't know the exact cable lenghts, but it is very likely to be just a tad bit out of the the specifications of 10GBASE-SR of the 82m on OM2 but it did work very well and I don't have losses (knock on wood)

I'd like to upgrade the other links with the same type of old fiber in the building complex to 10Gbit as well. However I know that they are going to be at least 20-40m longer and I'd like to play safe. (I'll have to work with what I have, however for a new link that was installed recently we were able to convince the contractor to install single mode where he initially wanted to install OM4, but that's only one new pair of 12 fibers from the core to a single building part.)

I later found the original datasheet from our old cables which classifies them as OM1, however it seems to be a "rather good" one for OM1, but not "good enough" to pass minimal OM2 requirements. The old datasheet I found, says:

• 50/125 diameter, not the more typical OM1 diameter of 62/125
• Bandwidths of >= 400 MHz*km @ 850nm, >= 600 MHz * km @ 1300nm.
  • OM2 seems to require >=500 MHz*km @ 850nm and >=500 Mhz*km @ 1300nm. $
• Attenuation should be <= 3 dB/km @ 850nm and <= 1dB/km @ 1300nm.

I'm leaning towards 10GBASE-LRM for the longer runs to play safe(r) - yay or nay?
And with OM1/OM2 it seems, mode conditioning cables may be recommend (or even required?)

Any cabling experts who could give their opinion? I'd really appreciate some feedback.