Cube options for Marauder Multishot build and possible viability?

[Edymos 1]

So just a general query, has anyone experimented with the viability of cubing Rimeheart and Frostburn for their stacking abilities? Or are percentages too low to be considered high-end GR viable? Seems like having Polar Station for your sentry perk, Multishot set with Wind Chill and having the Frostburn boost cold dmg 20% with 50% chance to freeze to stack with Rimeheart having 20% to put 10kx cold dmg on top with the set dmg from the sentries looks like a TON of dmg but the math seems to low for it to be any type of consistent. Anyone have any thoughts or has experimented with a difference? For reference my build is pretty far from optimized in terms of stat priority but t16 GR are walkthroughs. Thanks in advance for any replies :)