I use the Ornano kit for E-6 "KI90", a single-use six-bath kit suitable for rotary processors, and I am satisfied with the product.
The kit contains concentrated for 5 litres of each diluted solutions.
Depending on where you live, it can be easy or hard to find. In Italy is probably much more common than any other E-6 chemistry.
I bought my kit from an eBay shop, eBay user: Westernphotonline, which also sells abroad, but you should check costs and restrictions for hazardous materials first. You can also buy the single components separately.

The final bath in the kit is a "stabilizer", it contains formalin so it is suitable for old films or for modern non-Kodak and non-Fuji films.