bottom end reassembly

No, on crank journal only - if you must. I would recommend oiling the shells and crank journals and filling the crank with oil rather than using paste. Paste can usefully be used on the camshaft. Really only need paste, rather than oil, if you expect the engine to be sitting around for some time before you run it.

oil between crank and shell.  Not between shell and conrod - you do not want shells spinning in the rod.... Once the cases are together, then fill the crank with oil using a pressure can.  I fill the cam trough with oil before fitting the barrel, and dump some extra at the valve gear before starting.  It will go down the pushrod tubes and keep the camshaft and followers happy

I would note that the BE shells are securely and precisely located in the conrod; no chance of them spinning. A smear of engine oil on the back of the shells will help them 'sit down'. Commando doesn't have a useful 'cam trough' so chucking oil down the pushrods via the inspection covers is recommended before starting after reassembly or a winter layup. Section C32 of the workshop manual shows how to prime the crankshaft with oil once the engine has been fitted in the frame and before first start up.