15 wt. oil works too (that's the highest I'd go, I wouldn't use anything above this), that was the lowest weight that the hobby shop that I went to sold (not a dedicated RC shop but the price was right, $5.00 for like 5 oz of the stuff). It worked decently well.
The AI silicone oil is actually 5 wt. or 2.5 wt. (or so I'm told)
For slide lubrication, lithium grease or possibly graphite powder (that can be a lubricant too, which I just found out this summer working on renos). The guy you'll want to talk to about graphite powder is Illusion as someone told me that he uses it on some of his custom built GBB's.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE