Bludgeoning with a Being
When using a person-sized (or just slightly larger) being to hit someone with, here's the modifiers (assuming the being is grabbed) if only casual STR is required to lift the being.
|Being lifted is...||OCV||DCV|
|STUNned or otherwise limp||-1||-1|
|Unconscious or conscious willing and stiff||+1||+/-0|
If it requires more than casual STR to lift the bludgeoning being, a DEX roll is required. Failure of the DEX roll causes a -2 to the DCV listed above (additional! you're standing there trying to hold on to this thing while you're being attacked - and this assumes you do have some maneuverability) and the attack automatically fails. If the DEX roll is made, subtract 1 from the OCV and DCV listed above (additional).
If the creature is larger than a normal human but less than half a hex, add 1 to the OCV listed above. If the creature is larger than half a hex but less than hex-sized, add 3 to the OCV listed above. Of course if it is hex-sized, normal area affect attack takes place.
Soft cushy being (down pillow-like) -2d6 (or more if less substantial)
Soft but substantial being (water or air-like) -1d6
Lumpy being with bones (human) +0d6
Tough being (mutant like Slayer or Pterodactyl) +1d6
Hardened Armored being (robot or similar) +2d6
Damage is -½ d6 from the chart above if the being that is pummeled with requires more than casual STR to wield. The idea being it's not such a clean shot when you're flinging something around while straining.
The bludgeoning being, that is the being actually implemented as the attack, takes the same additional damage as above according to what it is hitting. So a robot smacked against a tough mutant will take 1d6 additional damage. Yes, in a sense one could argue it might take less but assuming a person involuntarily protects himself and also there's some velocity in effect, I think there should still be the same bonus.
Buying STR usable for others does NOT increase beyond these numbers. So to make your additional STR transferable as Rodin did, buy it up beyond the bonuses above. In other words, Rodin doesn't get 2d6 back just because he would otherwise qualify above. In part this makes sense as a creature who voluntarily allows his STR to be usable might have control over that except for the above boundaries. So let's say Rodin could control how hard he smacked with his 6d6. In stone form he wouldn't do more than the 2d6 above but he also couldn't do less. It's simply par for being a very hard object wielded by a strong person.
One could easily argue I should give larger bonuses but then that dilutes those who build their characters as Rodin has as well as basically gives away some free attack capabilities for any given robot or heavily armored being. So I think this is a good compromise.
Above of course subject to "environmental conditions" and special effects. For example, a tough being that can alter itself to not have a force field/extra DEF might be reduced to +1d6 for the damage it inflicts.