When I did one of my 261 engines,the rods were off on the top end,so I made adjustments by taking the lightest rod on the small end ,and put the heaviest piston on that rod.The engine is very smooth, so I must have done something right.
British bikes all have forged aluminum rods, the big ends have a web on the cap you can grind on, but they are usually very close in weight.On the pistons I remove material on the wrist pin side.
