Bandit-1 that 520 sounds great with the best of both worlds. However I knew that 5500 rpm would get your intrest up. As best I can find at rpms over 5500 is the reason for solid roller lifters. At that speed give or take all your roller lifters due to their heavy weight , compaired to flat tappet lifters, want to start not to follow the cam lobe and for lack of a better word flutter. The cure is heaver valve springs which in turn want to collapse the hydraulic lifter. Which is what brought about solid roller lifters. The more radical the cam the bigger the problem, that is why most cam companies only offer their most radical grinds for solid lifters only.
That is why your engine develops its max power at 5000. To try to answer the English Gentlemans question about wear is . With new engines as the valves settle into their seats and the rest of the valve train wear in you need to adjust the valves frequently, 3000 miles or so for two or three times untill the valves settle in their seats, then you can go for longer periods between adjustments. As for duribility the first soild rollers failed frequently due to lack of
oil at low rpms. Most all solid rollers including the ones in my 514 now have a extra
oil groove in the lifter to deliver more
oil at low rpms, which gives a lot longer life as the wear that Niles has measured indacates. As when to change them I am unsure about that one.