Do you weigh your pellets?
Do you wash them first?
Nope, just give them a few drops of napier and they are ready to use.
What weight range would you use on a 4.88 grain pellet?
Assuming you mean 8.44grain. Everthing between 8.3 and 8.5 is used for comps everything else is practice.
Does it make a difference?
I think so in both a physical and mental way.
Physically, groups seem to be tighter with weighed pellets.
Mentally, you know that there are no wayward pelelts that you are going to be used so any misses are down to the pilot not the rifle.