best bet is to have them fitted. Problem is thats a custom job.
Second best option is the accuwedge. fits under the rear pin/post and eliminates a ton of "slop".
FOr what its worth, I "bedded" an upper and lower together with stainless shim steel and bedding compound- didnt make a whip difference over the wedge- but IS permanent and doesnt fall out when swapping uppers.