I have been using the 100 grain brass insert on my older CE 150's and my Goldtips, but these do not fit in the carbon express 90 heritages, is there a weighted insert that would fit the CE 90's

None that I have found.What I did on mine was take the standard 5/16" 50 gr. insert.Then I put a blunt in my drill and then spin and file it down to fit my CE 90.It came out to 42 grs. after filing to fit.When they first came out Sipsey River had some 100 gr. inserts turned down for the CE 90,they came out to around 88 grs.This was before he sold Sipsey to Big Jim.Easton's new H-size brass 50-75 inserts that come with Beman Centershots fit close but not perfect.