OK, so from studying the Ka-50 trimmer system from all the way back when BS1 was released, this is my take on things:
For all those people preaching the press and release method of trimming, you are setting up people for bad flying. Press, hold and release is actually more realistic for those with non FFB sticks.
The problem is that the press and release method is what is used in an actual Ka-50 with proper control hardware.
The biggest problem with trimming in the sim right now and the reason there are so many posts and treads on this topic, is because most people fly using a non FFB stick. With a non FFB stick you have to release the stick in order for it to centre. This procedure usually take about a second or so and in that second, you have absolutely no control over the helicopter. The reason people are getting jumps in pitch after trimming is because of "errors" that accumulate in the autopilot with changes in flight parameters. This is actually normal and is what happens in a real Ka-50. The problem is you cannot correct for them because you are waiting for your stick to recentre.
The way a real Ka-50 pilot would do it is by pressing and releasing the trimmer button but since there is no wait for you stick to recentre, the pilot can immediatly correct for "error bump" and press the trimmer again. With each successive press of the trimmer the bumps get smaller until you would have a perfectly trimmed helicopter.
The way to do it in the sim is with a technique I havent seen mentioned before.
make a coarse correction without pressing the trimmer. When you are done, press AND hold. you should only have to hold it for a second but in that second you still have control and you can correct for the error bump. When the helicopter is stable, release the trimmer. This essentially simulates a real Ka-50 pilot pressing the trimmer 2-3 times to get perfect trim.