If memory serves, to swap the valve you need to un-crimp the can and re-crimp it to assemble. Not completely un-doable, but not easy either.
Could you grind a larger seat to fit a K24 valve into a K14 housing? I haven't ever handled a k24 to compare its dimensions to a K14 (maybe the k24 valve is the smaller of the two).
I can try and get you all the dimensions along with pictures if I try really hard tomorrow
I have a K14 wastegate avail. the valve travel adjustment is broken off though. I will see if its repairable this weekend. ( boosting around 25PSI currently stuck in its position)Andrew D