Hard call to make.
So much depends on the surface (mud, snow, ice, etc.). If ice, then chains as more weight may not improve the friction between the tire lugs and the ice.
If getting some traction (cold, packed snow or snow covered drive) then weight will help.
Crap shoot if the choice is one or the other.
I pushed 2-3' of drifted snow yesterday with the 7' blade and no chains with no problem slipping.
Last year, the same drive but ice (wet snow, plowed then turned cold) and same weight combination but lost complete control of the tractor and slid back down the drive (fortunately didn't flip into a ditch).