Thanks for help guys, I'll keep on searching! 

Hey does anybody think the Original 800 S resonator is available to buy at sennheisers or would one have to buy a whole driver for that..
Tips was the first attempt and IMO not as efficient. The best is to go directly to the current SD resonator.
why don't you contact Sorrodje directly?
I might be able to help you out
I will send him a PM and see what he says.
OK. Have you made them with the same materials as he used? What would you think is fair for making a set? I see that you both are in the EU and I don't know much about dealing with transactions from there. Do you do PayPal?
Edit: Sorrodje came through.....
Honestly, I tried different sizes and the 2mm one offers good results and is still easy to work with to make the resonator. I Still think there's some room for improvements but Dunno it will still stay easy to DIY , to produce in small series and to remove in case of. Let's say the current State od the SD resonator is a good compromise.
Hope that makes sense.
I don"t really care about serial differences. Measurements and experience show it does not matter much. Balanced cable makes a difference if and only if the amp is designed to wiok better in balance mode . I've not much experience with EQ unfortunately so I can't tell anything about it.