I use a 50/50 mix of Vasoline brand Petrolum jelly in Gel form and K/Y Personal Lubricant to thin it out some. I mix em in an old blender, let sit overnight to let the air bubble settle out, and you've got some fine lubrication my friend. Don't knock it till ya try it. Silky smooth....shifting.
Whatever is cheapest and I can get my hands on as long as it meets the SAE requirements. I mostly make short trips so I prefer to change my oil more frequently and running expensive oil stopped making sense a long time ago.