Worry about it less. Unless you have some specially horrible local grit there's no reason to service a headset frequently. Will assume that this bike does not see a lot of rain, that you use the fender bikes on rain days. Will assume a '72 Pro does not see trail riding. Headsets die from brinelling. Brinell is primarily caused by too tight bearings, not ordinary wear. Or they die from long miles with completely dry/absent grease.

Perhaps installing a less dear headset would still your fears. The shop I worked at took all the variant/oddball/non-catalog Raleighs and Carltons that showed up at Raleigh Midwest. Pros and Flyers did come with every imaginable headset. None of them were wrong. Even Hattas and Tanges showed up in early 70s. Brampton frequently. Plain Raleigh headsets. If you want to do the shorty fender at least get Bluemels.