+1 on Retro's theory of clutch usage
just to add some more info on composite at least with the mugen shoes the mugen White shoes slip less than the carbon black type but slip more than alu, so you have a bit more tuning options there as well if you do run them then cut about a 1mm of the end so they sit better at rest.
I run 2 alu with 1mm springs and 1 white mugen composite with .9 springs no problems with wear at all and it works fine, as stated start off with a new bell if doing this.
You can stick with 1mm springs and tune the shoes for engagement by drilling them out as personally i find the 1.1 to be a bad fit in most clutch shoes and require removal of material to not bind, so if i want a more aggresive clutch i would normally drill some material from the clutch shoes rather than heavier springs, just my preference though