I'm trying a delivery case where my lab report says, "tar substance" that "contains[THC]." All the testimony will be that the CI arranged to buy "hash."

I have a DRE, who went to some training in CO on marijuana, on deck to come in and testify on effects, potency, etc... I'm open to suggestions on how to shore up this angle.

Any tips on how to get out in front of the "hash is really just weed, and that makes this a misdemeanor if you really care about a little grass" argument?

I think your DRE is exactly the guy to do it. Just ask him exactly that. "What's the difference between hash (a THC concentrate) and weed?"

Hash is the same thing as weed in the same way that a 12 oz glass of Everclear is the same thing as a can of Bud Light. The main argument about why weed should be legal is usually "It doesn't get you THAT messed up! Drinking is WAY worse!"

But hopefully you DRE can help clarify that smoking hash is gonna get you way way way more messed up in much more intense ways than smoking weed. That's why it's more expensive, more rare, and why it's a felony to have it vs. a class B misdemeanor to have a joint.