Zed has seen this reaction performed. It does produce a one pot DMT synthesis. And, yes, the yield is actually about 25%. I don't have the paperwork. But, as I recall, Ethyl Bromide or Iodide is added dropwise to Magnesium in Diethyl Ether, to form the Grignard reagent. Indole is then added slowly to to the reaction mixture to form a 1-Indole Magnesium complex, Which there after, is reacted with Dimethyl-Amino-Ethylchloride, to produce DMT. This Reaction, unlike many you find in Chemical Literature, actually works pretty well!
The Downside was, that at that time, Indole was a pretty tough acquisition. And, Dimethylaminoethylchloride wasn't easy either, seems folks were using it in some opioid synthesis. There were not as many Phychoactive substances, and the Feds could focus a lot of attention, on just a few precursers. So, the ones they did focus on, they could squeeze pretty tight.
That being said, the difficult part of this synthesis is in the execution. Ordinary stirring will not do for most proceedures. The additional solvents employed, and the cold temperatures we used, created a thick peanutbutter-like reaction mass. No ordinary stirrer can move this stuff. You must employ a powerful, explosion proof DC Motor to provide the required stirring. Also note, that a fair volume of ethane gas is released, don't be surprised.
Anyway, that was the old way, thanks for the great references, I'll cruise for improvements.