I've kept powdered MHRB for at least 2 years before and didn't notice any significant difference in the end product yield/quality, however the bark was stored in the fridge so it's not the best comparison. Even so, I wouldn't think the stability would be that different at room temperature.
HarlequinEntity wrote: after pouring of most of the naphtha and drying out what appeared to be white DMT when it dried it was a yellow color that was also sometimes orange brown and never completely dried out.
In that case I probably would have tried to clean/recrystallize the product with naphtha: Put the impure extract in a vial/jar and add a small amount of warm naphtha, just enough to dissolve the DMT. The DMT dissolves in the naphtha very well while the yellow, oily stuff mostly stays at the bottom of the jar. Then decant out the DMT-containing naphtha into another jar while being careful to keep the oil behind. Then freeze precipitate out the DMT. You can repeat the process if needed.
If your new batch turns out the same way as the first maybe give it a try and see if it cleans it up.
What was the reason that you chose to go with xylene and d-limonene? I was under the impression that they would pull even more alkaloid impurities than naphtha, but I'm not certain as I've never used them.