Hey there hockins! I recently encountered the same exact issue as you, and I hope maybe I can save you some time with the stuff I've tried. I have a dt3 which from what I understand has a nearly, if not completely, identical stator to the dt1 and dt2 (old heads, please feel free to correct me). It sounds like yours was rebuilt by DEET and he's got quite a reputation around here, so I think it's reasonable to assume that he's probably done a good job with the stator.
As far as your "testing setup" goes, all you should need to get a spark is the black wire from the harness, your ignition coil, and spark plug. Attach black wire from harness to single bullet connector of the ignition coil. The ignition coil NEEDS TO BE GROUNDED, I learned that the hard way; I used a wire and wrapped it around a bolt on the frame and the hole in the coil core. Attach spark plug boot to your plug, and touch the side of the spark plug to ground (a nice clean bolt on the frame works nicely). Make sure you are spinning COUNTER CLOCKWISE i.e. the direction the engine runs! I made that mistake and it does, in fact, make a difference.
So now assuming you have done the above and it still doesn't work, let's work through some troubleshooting options. Firstly, check that spark plug gap. I got mine brand new from the shop and assumed they had gapped it right, but they didn't and so I did it myself. If you still have no luck, next thing I might do is try to take a reading of the voltage output of the source coil like RT said and like I did. I personally used an oscilloscope which was a fantastic tool to visualize EXACTLY what the coil was putting out, but that's a tool that few people have access to (I only had one at my disposal because I go to school for engineering, and I had to roll my motorcycle through the lobby and into an elevator to use it). If you have one you could use, it's the perfect diagnostic tool though. If you're normal and you don't have one, though, no worries. You can make do with a multimeter like the rest of us.
Quick info about voltage measurement in general - I'm sure you are all familiar with AC and DC as concepts, and if you are you'll know that AC is a bit more complicated to measure than just saying a number of volts. Since true AC is constantly changing voltage and polarity, the voltage is a different number at any given moment in time. The solution that electrical engineers use is to give an RMS value, which stands for "root mean square." This is a mathematical operation that can be performed on any continuous function, such as the sine wave that voltage in AC follows, that essentially determines an "average" value of the function, or in this case, voltage. So when people say that wall outlets provide 120v of AC electricity, they are saying 120v RMS, meaning that the peaks of the voltages are actually higher than 120v.
When I did my oscilloscope readings, I was mostly interested in the peak values. If you get a multi-meter and hook it up to your source coil, though, you will get something closer to the RMS value (depending on if you have a true RMS multimeter or one that takes shortcuts) which will be considerably lower than the peak values (and probably closer to 6 volts, I would guess). There is a button on some nicer multimeters that says "peak" on it which will tell you the peak value instead of the RMS value, which may be easier to compare against my readings.
If you want to measure this, make sure you take the leads of the multimeter and put one against the black wire coming from the stator and the other to ground (bike frame), and then give it a spin with the drill (technically either direction should work for just measuring coil voltage without points). Blocking the points off like RT said will be helpful as it will make the system perform more like a true AC signal which is easier for a multimeter to read. I have all of my oscilloscope data and I can share it with you if you'd like, I could also maybe do the RMS calculations as well for my values to compare to your multimeter readings assuming you can't get one that can read peak values.
Let us know what happens if you give this a shot! If your numbers are looking wrong, it would be worth examining your stator to see if something's amiss there, including checking the coil resistance. If the numbers look good, it might be worth checking your ignition coil. Wishing you good luck!
