My suggestion is you remove the weight under the watchful eye of an experienced bowyer. My experience reducing a bow 10#’s is to treat it the same as tillering the last 3-4 inches of any selfbow, especially a recurve. Depending on the amount of bend in the limb, and where it is, will affect where and how much wood to remove. Removing wood evenly along the length of the limb will drastically change the tiller. Think about it, if your tiller is dead on when it is 3” short of the draw length at the desired weight, do you remove wood evenly or in different locations to fineness it into desired arc?
Said another way, currently the limb varies in thickness and width which determines the arc and how the tips open when the bow is drawn. Removing the same amount of wood throughout the limb will change the ratios of wood to thickness, thus causing it to bend more in thinner areas and less in thick areas.
Go slow, be careful, use a judicious eye, and quit using the palm sander at around 5#’s above the weight, if you use one. Oh yea, use 120 grit paper until 47#’s and then switch to 150-180 down to 45#’s, and 220 after that.