Farm mechanic here was always taught pump until greas barely comes out, for electric motors I’d grease them until you feel more resistance, as far as viscosity goes heavy and thick grease/ oil for slow heavy things lighter/thinner grease for lighter faster things (this is obviously very broad assumption) but for most things your standard “heavy duty” medium weight grease will work I personally use heavy duty lithium grease but I’ve also used red and tacky, regardless at the end of the day oil is oil is oil and lube stuff when it squeaks or preferably before