They don't make any brass inserts for the CE 75 or 90's I've found.What I did on my CE 90's when they first came out was to take some 5/16" 50 gr. inserts and file them down to fit.I mounted a blunt in a drill,spun on the insert and spun it and filed to fit.Didn't take that long,came out to around 42 grs.When John of Sipsey River(before he sold to Big Jim) started selling them he took some 100 gr. inserts to a machine shop and had them turned down to fit the CE 90,they came out to around 88 grs.You may try some Easton/Beman H-size brass inserts to see maybe if they will work,the ones that come with Beman Centershots.Both CE 90 and Centershot's are a 9/32" arrow,I'm not sure how close they are.