It's not a question of 'EMT police'
You have discovered that it isn't that easy to fit standard cartridges into EMT headshells, and you don't have the possibility to make full adjustments once fitted. Therefore it doesn't really make much sense to try.
Apologies for resurrecting an old thread here, but I couldn't resist replying to this.
I had the opportunity to purchase a 948 from the aforementioned Irish National Broadcaster last year. Although it was described as being in 'excellent' condition and as having a TSD15, it needed a bit of restoration work on my part (mainly hovering 30 years' worth of fag ash and the odd paper-clip) and actually had a cheapo Stanton MM cart. (There were also numerous problems with the arm lift motor, but that's another story).
As well as fitting a new TSD15, I also got my hands on a very rare black EMT J-Shell - this is basically an EMT manufactured head that will take a standard length cartridge, but is compatible with the 929 arm.
Rather than modding the 038 MM card with J.P. Van Vliet's step up transformers to turn it effectively into a 088 MC stage, I purchased the Fabritus' F2 cards, so now I still have the original 038 card with the option to go back to an MM setup if I want.
There seems to be a lot of EMT collectors out there with very deep pockets, especially in Japan. I saw a ex-BBC 950 sell for over 7,500 last month on ebay. I was tempted myself, but I didn't fancy having to face the inevitable divorce proceedings.