Goal weightage to set to Max 40% for each Goals

Hi

We have come up across a requirement where each goal weightage in a Goal Plan should be Set Max 40% , This is required as the business' needs Min 3 & Max 5 Goals in a Goal Plan we already have 100% weightage an max goals set however will require the steps to configure 40% weightage to each goals please let us know if the same is feasible and will an auto complete rule has to be defined in this case