To clarify ... Lithium grease is lithium grease regardless of the manufacturer just as 10w-30 oil is 10w-30 oil, of course it nice if you stay with the same manufacturer (at least they will say so) but nothing catastrophic will happen if you use the same type of lubricant from different manufacturers. I know not everyone will agree with that statement but if you do not I suspect you have been subjected to some really good advertising or sales pitches.
I also grew up on a farm and as Sting stated we didn't worry about brand, age or anything other than "quantity" of grease on the bearing ... I have to believe it was because of the low speed most of the equipment was subjected ... never more than 20 mph. My dad was more particular about what went into the family car and the trucks and tractors, which got regular maintenance recommended by the manufacturer. Thus I would suggest maintaining your Hi-Lo wheel bearings according to the manufacturers recommendations ... especially you rebels towing them 80 mph down the interstate!