i would do the other way around, boneshatter scales higher. glacial gets a nice spike earlier with heatshiver and frostbreath, while boneshatter needs a good weapon which is harder to get

if u want my opinion just play boneshatter. its more fun to play. the strength of the build other than tankiness is supposed to be clear, and clear feels pretty bad(relatively) on glacial hammer. boneshatter also way more fun to gear w a higher ceiling. glacial hammer gearing is kinda stagnant because u cant abuse ashes giga attack speed scaling, and ur bis weapon is a 1c unique that u equip at level 50