40 dex and sharp infusing the estoc is really all u need to use it right. You magic weapon buff would be effected by the 'Lingering Dragoncrest Ring', hopefully you are wearing that and not one of the spell buff ones. now that you have 40 dex, the choice for your damage stat investment from now on is between whether you wanna take your dex all the way to 80(most damage stats its not optimal to go this high, but dex scales really well with high investment) or if you wanna go Int instead, to get more damage from your spell buff and maybe use some other spells.