Spectrum Gelcoat

Hi I Just went on "I" boat to order my Spectrum Color Gelcoat 1988 Taffy Ivory for this years repair's. I purchased 2 quarts last year one was so close very little tinting. The second one was so dark I could not even tint it enough to bring it back. I am not here to bash Spectrum that' why I was trying to order more. I purchased two other quarts of gelcoat white and tried to tint them myself. I tried small amounts large amount and I could never even get close to the taffy ivory color. A lot of wasted gelcoat . I have a large amount of tint in my shop but do not have an eye for it. Does anyone have a solution ?  talked to body shops they mix by a formula. Thank You Joe