I have trouble getting my Kefir to cleanly separate on a consistent basis, despite allowing it to sit out for multiple extra days, prior to refrigeration. As my house does not remain at the same temperature year round (nor day-to-day), I suspect temperature is a major contributor to the problem. I have tried heaters, and although I can get the room quite hot, the separation is minimal, just as without the heaters. Is there a special heater, etc. for this separation that would work for kefir cheese?
With milk kefir, if you over-ferment it, you will see it break into at least two if not three layers. Slightly cloudy whey is one of them. Without that, you can strain out some grains, but getting a curd is going to be difficult. You can try acidifying the kefir with lemon juice or vinegar to coax out a curd, but it would be much easier if you let it over-ferment. That means patience (many days) if you have a cool ambient temperature or you can somehow keep it warm (say 30C) for a day. The type of milk matters too. Homogenised fresh milk tends to be harder to work with, and UHT tends to be easier.
You need to see a distinct layer of whey first before trying. It should not take more than half a day to strain out the curd. Salting the over-fermented kefir before straining also helps.