Generally speaking, roller rockers are only used where high performance is desired, and the use of a higher lift camshaft can cause quite a bit of fitting and running trouble unless it's done just so. For the money, I think I would rather have a slightly higher performance cam and leave the stock (rebuilt of course) rockers in. Rebushing them is something any competent machinist is capable of doing fairly inexpensively. Bring him your new rocker shaft, (the tuftrided one I hope) so he can hone them to exact size. As far as the contact tip goes, you will indeed need to sand down the scarred tip while making sure that you are staying square to the axis of the shaft. A belt sander, with a means of keeping the tip parallel to the shaft axis, works great. Be careful, the material, will come off rather quickly. Once this is done, find a buffing wheel and some compound for steel. There are two grades you should use in progression. The first is called the "cutting compound". It gets down to the smooth surface right away. Be careful you don't go too far; just untill it has "touched out" the entire surface. Now charge the wheel with polishing compound (buffing, not paint polishing) and have at it. You should be able to get a Chrome-like finish. We do this so that the rocker tip slides more easily across the valve stem top surface and will last tons longer than the original. The factory never bothered with this, and if you look at the tip on a new factory part you'll see that indeed the machining process used left lines across the tip, which is the opposite of what you'd like. Let me know if there are questions.
Motorbill
Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon