And right here is the problem^^^^, it's not a simple question, and intended usage has a 50% affect this decision....the important thing is the total package.
Per the OP He's only got the stock front 3/4" bar from a '73 & up, that's not enough to use a rear bar w/the ESPO's. The frt .870" T-bars are a bit soft, but here, the usage DOES matter. Rural roads, especially like Mine, have a lot of rapid elevation changes.....straight on or mid-turn, like a ralley, so more stored energy does a better job keeping the tires in contact with the road when the suspension moves into rebound.
Basically, the OP needs a bigger frt. bar, before considering a rear one. And the best shocks He can get.