About 30 years ago (Wow! It's been that long...) I worked for a place that sold parts in the front door, and had a full machine shop in the back. On my breaks I used to watch the guys turn cranks, bore cylinders, cut valve seats, re-babbit bearings(!), etc, and for the life of me I don't see how one could have only one journal turned. Nor could I see the utility in that, as the crank would already be on the machine....
In my opinion, grind 'em all, or, as has already been mentioned, find a crank kit.