Welcome to the Nexus!

What is your smoking method for DMT, if I may ask? going through 500mg in two sittings seems to imply to me there is a lot being wasted, maybe burned ?  If you plan on having a longer relationship with DMT or if you smoke weed too, I suggest getting a GVG, it will make your vaporization method way more smooth and effective.

You say you only tried DMT at that time, are you planning on extracting and trying again? And/or maybe taking it orally ?

As for the powdered vs whole caapi, I never gotten pre-powdered caapi vine, so I cant compare by experience, maybe someone else will chime in. What I can say is, regardless if you dont get it powdered, be sure to break/powder it as much as possible before brewing to get most alkaloids out.  Will you add some dmt admixture to the aya? Which? What dosages are you considering?

Check the supplier section for good suppliers. Good luck!