I could have this wrong, but I thought 70 vs. 71 vs 72 were basically incremental upgrades over the years. Minor changes, enough to merit a number change, but pretty much the same. Might be wrong about that though. It certainly isn't made very clear when they use one part number and a different photo.

Anyway, I have the disc version of one or two of those. I think one is a 70 and one a 72, but I'm not sure. I have no problem with either of them, but neither is hooked up to a dynamo light at the moment. But one of them remains my daily commuting tire with no issues. When they have been hooked to a light, they also had no issues. If I paid attention when turning on the light, I could feel the slightest increase in drag, but it was only noticeable at that moment and then became imperceptible to me.