Rubber vs Poly in Leaf Springs

I used poly bushings in another project but found it to harsh for street driving.
Has any one used a poly/rubber combination in their leaf springs before especially on the shackle side. I'm definitely going to be using rubber in the front leaf spring bushing. Just trying to decide if maybe using poly on the frame end of shake or the leaf end of the shake would be of benefit without being to harsh.
Thanks

Farna I was thinking the same thing, thanks for your opinion

Urethane can be compounded in many durometers from bowling-ball hard to soft as a sponge. Aftermarket urethane bushings are often made in a higher durometer than rubber bushings to reduce deflection and allow the springs and dampers to do their job, rather than deflecting the bushings excessively first (rubber or urethane bushings act as both a spring and damper ... higher durometer = stiffer spring & less damping, lower durometer = softer spring).

I have urethane shackle bushing and it made a noticeable improvement over stock rubber ... but expect rubber replacements would have also made an improvement. Not too harsh to me, but everyone has their own preference.

Biggest thing is to make sure you tighten the bolts when the suspension is in its normal loaded condition so you don't induce unwanted pre-load in the bushings ... with rubber or urethane.

If you want something tunable for comfortable ride or better handling, fit adjustable dampers (adjustable shock absorbers).

Hope this helps,RD.