a nice set of W&W NS foam ILF limbs, 38/68. 400 TYD

Looking for suggestion on making a 400 spine arrow work with my setup. Already have the arrows. Shooting a tradtech titan 40 lb limbs but looking at going up to 45 lb for hunting. DL is 29.5” Normally shoot 500 spine with 175grain up front, tip + insert. If 400 is too stiff I would just sell...