i recently found i could get either of the duel kits (warshpinx and knight) and do some modeling work to make both models that come with it so warshpinx and necrosphinx orr knights and stalkers but im having a hard time choosing which one!

I'd go with the Sphinx kit for now as you'd then also have the option of turning the other 'half' into a Heirotitan or Colossus, as well as getting a Tomb King/Tomb Guard and enough gribblies to make a base or two of Tomb Swarms.

If you don't have a Hierotitan already, I agree with Anvildude. Once that base is covered, though, I would start investing in Necropolis Knights.