Woodleigh Weldcore is NOT a cast bullet it is a jacketed softpoint, which meets the requirements for an expanding bullet.
Doubletap ammo does not sell a cast boolit load for the .35 Whelen.
To my knowledge, Doubletap doesn't sell boolits and doesn't load .35 Whelen with cast boolits. I could not Google any .35 Whelen ammo with cast. Where you getting your information? Links would be really helpful.
However. If you can find someone to load some ammo for you with cast bullets. Any cast boolit with a LFN or WFN profile, regardless of hardness, out of a .35 Whelen, will kill a whitetail deer. If you put it in the vitals. Except maybe some cat sneeze plinkers using light .38 spl bullets. Any game warden. Anywhere. Seeing a non-jacketed bullet in a .35 Whelen will not question you.