Tow bar - how long?

Ok, be gentle. I've searched many flat tow threads and haven't seen this talked about much but, how long should the tow bar be made? I'm fabbing my bar next week and i'm torn on the length. The bar will never be folded up and driven.
I'm getting a 20' stick of 2" square tubing, 3/16" wall. I've pulled many trailers but never "officially" flat towed. It seems the further away the towed vehicle is from the hitch, the more smooth sways may be. But, it would have more leverage on the towing truck. I'm not sure of how the free front wheels of the jeep would affect this. What are your thoughts? The standard ~ 4' from ball to bumper, or more like 6'?

 

I dont know mine is behind me at a little over 4 foot long ok maybe closer to 5 , I think the standard is closer to 3.

 

That's cool. How fast do you tow? I like to haul some ***, so i'd like to know what most are comfy with as well.

 

I have 5.38 gearing so the pinion is really zipping along so I keep it under 70 and check the pinon temps along the way just to make sure every thing is happy . If I had higher gearing I would go as fast as need be with out worry . My dodge doesnt know it is back there, my mpg drops from 21.5 to 20.8 on the lie o meter.

 

Thanks, nice to know. I have 3.73's and will have a Dana 300 soon, so I'll be dropping the driveshaft anyway.