Final length trimming should come after the shafts are installed. This way the shaft tip weight variable will be accounted for the in the length. You can add a little more tip weight to account for the 1/4 inch you will be trimming. You can dry fit the components, add the tip weight, measure again and figure that the additional 1/4″ will account for about 3/4 to 1 swingweight point. So, if the tip weight was 4 grams, you may need to make it 6 grams to account for the 1/4″ additional length you are going to trim. It is a little bit of a pain if your trying to be dead on precise, but it’s what you have to do. I am guessing a little on the swing weight effect of the estimated 1/4″ length add due to the tip weight. Understand that not all the different weight tip weights will have the same dimension (not all will be 1/4″). In short, if you add a tip weight to get the weight that you want, but then want to trim more from the butt to get the length, you will need to add more in the tip. You will just have to calculate that as you work through the set, based on the tip weight you add.