I have the problem of uneven extraction. I'm using a rancilio silvia with a baratza preciso grinder. I've worked on tamping differently, as well as evening out the grinds. The right hand spout pulls consistently faster. What might be my problem/ how do I fix it?

First thing to check - is the machine level at the grouphead?

Best way to diagnose these kinds of extraction problems is to use a naked portafilter. With the spouted PF it's hard to tell what's really going on. Are you sure the uneven flow is not due to some unfinished material causing it to favor one side of the PF? Maybe try running some water through the PF and see if it favors one side.

You can also try WDT - basically stir the grounds with a thin stiff object to improve the distribution - and see if that helps.

It's also quite possible you're consitently tamping off axis. After tamping, with the tamper still sitting on the puck, hold your pf up to eye level and look at it from at least two angles to see if the tamper handle leans to one side (like the leaning tower of Pisa). Honestly, I'd check that first...it's cheap and easy, and really fast.