Is having a poly bushing at the axle housing and poly bushing on the upper control arm going to lead to early bushing failure or worse?

I currently have a Del-sphere joint on my upper arm, but it is way harsher than the poly bushing that was on there. I don't like being able to feel the moment when my tires slip and starting from a stop it's very noticeable when the slop in the rear end is taken up.

Driving down my dirt road is pretty harsh with the washboard effect. Cruising on the street doesn't feel much different. Nor do big bumps, it's the sharp bumps that suck.

So has anyone been using a poly/poly setup on the upper arm for any length of time. I can tell it's not allowing the rear end to roll as much in turns and my upper control arm jam nuts were pretty loose when I went to change it, but other than that it great.

I have spohn poly/del-sphere lower control arms.

 

Well I put the poly end back on. I couldn't find much info googling it, just a few stories of mangled mounts doing auto-X. My main concern is the upper control arm breaking at the bushing tube.

 

If there is some kind of free rotation in the upper arm than polly at both ends would be fine. J&M makes an arm with a poly ball at the car end and you could use that with the poly bushing in the pumpkin. They don't sell it that way leaving the extra poly in the pumpkin up to you. Metco make one with a bearing for free rotation.

 

I read the Metco was noisey, which I'm trying to avoid. The J&M maybe the best option.