Best solution is to take one of the nipples you have in the car out and either size it yourself or bring it to someone who can. The same applies to the top. There are a large number of theories as to what is best to put into the top of the suspension - I use a "light" grease.
Is it worth it? I don't know, but as the manufacturer saw fit to give me a grease nipple on the top of the suspension, I feel bound to squirt some grease in!!!! Sure as hell can't hurt.
Cheers!
