I'm not really sure I follow what you want to do. Define "normal splice".
My preference is to change out the sheaves and use all rope halyards. The only time halyards have issues in the sun is when the cover is stripped, and they've been putting coatings on the cores to make them more UV stable. In addition, if you don't care about the extra weight, leave the covers on.
Merit 25 # 764 "Audrey"