So I am a snowboarder but decided I wanted to do something during the summer months so have bought myself a cheap second hand fake "penny" and normal skateboard ($15 for the two) and when i was looking at them they didnt really roll very well so I WD40'd them and they were better but still naff. I have taken the bearings out and they are very stiff

Penny - ABEC-5 ZZ809
skateboard - WZ Z809

So I started reading about bearings and came across this - https://www.youtube.com/watch?v=PJeEnaJs9FU and the first comment is from a bearing engineer who in summary says
Fact 1 , 99.9% of ABEC ratings stamped on 608 bearings are FAKE
Fact 2, Even if they were real, they would not effect the speed performance or longevity of a bearing used on skate board, in fact that would make it go slower (but only by nano seconds)
Fact 3, The highest possible ABEC rating is 9, there is no such thing as ABEC 11, ABEC 11 is beyond human engineering.
So why do some bearings spin faster and longer than others?
One word guys. LUBE
Most important of all you want to make sure you get either C3 or CM clearance. This denotes the size gap between the inner and outer rings and is slightly larger than standard, giving you a better spin.

He basically says get cheap bearings and lube them well

I understand the RS bearings are better as they are easier to clean

So I am going to get 2 new sets of bearings so questions....
1) what should I get?
2) What lube to use? grease or oil? I do have some of this grease from Bunnings, but is it too thick?