You can run a 520 chain, but if its a commuter bike I would slap an oem size a 525 or so.

You dont need to spend big money on an expansive chain there all mostly the same. I like basic RK chains ive had good luck with them. VERY IMPORTANT make sure to buy a rivet on master link vs the clip on that fly off and cause serious damage.

Best to run steel sprockets vs the aluminum which will not last aslong.

The way to check chain tension, put the bike in first gear. Roll it back and from the buttom you should have 2-2.5" slack. I never liked to keep my chains tight, because a too tight of a chain will not allow the swingarm to fully swing.

To clean a chain I like to use kerosene (or wd 40) and a nylon brush. DO NOT DO NO try to clean the bike on a rear stand with the engine running. You will lose your fingers!

As far as lubricants, I like to clean the chain. Take for a spin around the block to heat the chain. Then I spray maxima wax all over to protect from corroding, then I take a oil squirt gun and fill it with 20/50 motor oil I use that to lube the chain every 2nd ride.

When I use to race my aluminum sprockets end of the season looked like new.