champion rockers and lash caps?

The use of lash caps is more dependant on the valve than the rocker in most cases. Valves with hardened tips may not need caps. The increased area the caps provide is a good thing for several reasons. If your geometry will allow it, use them. Important to check that the cap bottoms on the top of the valve and not the lock or retainer. I have used them with and without caps on 390s. Also as a point, the exhaust valve is many times shorter on stock valves to account for the lash cap in geometry. Also many times, aftermarket stainless valves are longer than stock. Good luck
Your SS valves MAY or may not need caps per the manufacturer. If they are aftermarket, its best to find out if they have "hardened" tips or not. If they are the"stock" SS valves, i have no idea. Never used them.
55lb springs cause a lot of wear. If you need them then you gotta have them but they create a lot of stress. I would probably use the caps.