Charlie, I have 42 grain adapters for the Deltas. If memory serves me correctly, vary by a few grains anywhere from 170 to as much as 180 with the adapters. I have some 2018s as that is what I used to shoot. I love them by the way. That said, the only ones I have are too short. I have a 175 gr field point and the back of the point is overlapping the shelf by a quarter of an inch or so. They are cut at 29". That said, they show just a touch weak as a bare shaft. To hunt with them, I feel like I need to cut them at 31" at least and I am guessing that that will weaken them even more.
I do like the weight of the 2018 better which is why I am curious about a 2215. It looks like the spine of a 2215 (.419) falls between a 2018 (.464) and a 2117 (.407) but weighs less, maybe 50 gr on an arrow.
The weakness my 2018s show would probably be acceptable but I suspect (although I haven't tested it) that I will move into unacceptable if I add an inch or more of arrow. I know that 1/4 of an inch can make a huge difference with the carbons.
I may be overthinking the whole thing. Had I not shot a bare shaft, I could have shot 2018s or 2117s and been perfectly happy. Fletched, they both seem to fly great, although I know my 2018s are too short.
Thanks for your comments guys.