'Interference fit', hopefully tight enough to avoid rotation if there's any binding - if that happens I'll bung in some loctite! I've used the same technique in the crank-head bearing and for the bearing in the valve rod fork (all bronze in steel). Can't wait to see how it works in practice!
Next up is remaking the eccentric (simple exercise but too much play in the first one I made) then the rather trickier eccentric strap and rod. Still not sure how I'm going to do that!
Mate, if you make some little oil cups, with about a 5BA stem that's just long enough to engage in a dimple in the bearing bush your problem is solved. You'll have to bash the bearings back out to tap the holes tho'
Wot I do is drill thru the bearing housing with tapping size drill, insert bearing and drill a little way into it (just a dimple) thru the drilled hole. Make the oil cup with a no.60 or so delivery hole and jud screw it in - now follow the no.60 hole thru the bearing with a drill. Quicker to do than describe.