Reworking the 273 Adjustable Rockers

(1) there is a slight "trough" worn in the rocker arm tip where it contacts the valve tip. (2) I checked them on mockup & I'm OK (3) I think the chart wants a 11/16 drill bit but in my exp the tap tends to be too tight in alot of cases with the stated bit dia so I go a bit larger tho a 23/64 might be hard to come by & I've been sitting on this pump for awhile so I dont remember what I used exactly and more often than not it taps too hard so I go at it with a straight non tapered porting burr around and around carefully as to keep the hole concentric. the valve grinder has the swing arm attachment to do the rocker arms. just a touch to smooth em up, but what am I missing on that machine???