For a while I have been using Rocol RTD spray and found it to be very good by also very smokey by the time I had done a fair bit of cutting. I even got to the stage of installing an extractor fan in the workshop to suck out the fumes from it.
But someone gave me a tub of Rocol Ultracut Evo 250 to try. Its superb!! Used it today for the first time. 1 in 20 mix with clean water and used a small spray bottle to apply it.
Very little fumes from it and its not as clingy as the oil based stuff so the chips clear better as well. I like it alot.